The BBC explains its position on measurement units

A reader of Metric Views has received an unusually comprehensive reply to a complaint about the units used in the the programme ‘Bang goes the theory’. We are posting the letter in full as we feel it may be of interest to our readers.

Late in August, this letter was received by one of our readers from the section at the BBC that deals with viewers’ complaints:

“Thanks for contacting us again regarding BBC One’s ‘Bang Goes the Theory’ on 4 March. Please accept our sincere apologies for the long delay in replying. This is most unfortunate and regrettable especially as you’d taken the time and effort to contact us.

 The moment has passed somewhat, but we did at least want to reply to the points you raised and to apologise because the last thing we would want is for you to think that we had chosen to simply ignore your email.

Your complaint has been escalated for review and it does appear that we missed the central point of what you were complaining about – please accept our apologies for this unfortunate oversight.

In terms of units of measurement, the BBC is in a difficult – perhaps an impossible – position because we have a duty on the one hand to use relevant measurements, but on the other we have a duty to ensure as far as possible that our content is easily understood by our hugely diverse audiences who will have vast variations in understanding and knowledge. We have to try and marry the need to aid general understanding against the risk of alienating audiences in whatever terminology we use

Therefore, even when discussing measurement you may hear a velocity expressed as miles per hour and whilst this might not be the correct unit in terms of the original scientific data and calculations, in the UK MPH is far more widely understood that KPH thus the figure is translated to make it more understandable and relevant. We have to make our content accessible to all and a programme like ‘Bang Goes the Theory’ is at the forefront of making science and technology accessible.

There’s no suggestion that the BBC is attempting to mislead by the use of these measurements – in the ‘Countryfile’ example you mention, clearly acre is still a very widely used term in the UK with a very wide understanding of the size the unit represents. Of course, official forms may use hectare but that doesn’t make our data wrong, it’s merely a translation of the figure into an easily understandable form for viewers who may not be as familiar with the metric version. Thus it’s not incorrect as such, just a different expression of the same thing – an equivalent value.

Sadly this is an area where we simply can’t win. For example, we have vocal complainants who believe that all our weather forecasts should still use only imperial units and elsewhere we have complainants who believe that we should use metric measurements for absolutely all references including, say, speeds on UK roads (which are, of course, still in imperial MPH officially).

Another example would be vehicle economy figures. Across Europe these are litres per 100 km or similar, but here in the UK we still generally use miles per gallon even though it’s not possible to buy fuel by the gallon any more – it’s simply that MPG is a far more widely understood premise than the metric equivalent. This may change in coming years and if and when it does we will obviously reflect that.

The best we can do is try and use terms which we feel make the most sense to the everyday viewer who, unlike yourself, won’t necessarily have an expertise in the area being described.

The BBC is charged with reflecting modern Britain and as the country changes as does language and the use of measurement units – for example metric is becoming more and more common whilst some imperial and other measurements are still in general use – thus the BBC will continue to change with the times. To use the weather forecasts again as an example, data is generally shown in metric on graphics, but the presenter will often supplement those figures with inches of rain or snowfall and suchlike. Details like height are often described by official bodies such as the police in metric units, but at the present time it’s argued that feet and inches are more widely understood thus we may use that unit or both

We hope this helps to set the matter in context – in essence, our mission to educate and inform does to a degree have to take in what is easily understandable by the majority of audiences and even if it might not equate to the specific scientific references our figures will be accurate as being a conversion or the optional / supplementary unit.

Please accept our apologies again for the delay and rest assured we registered your further comments on our audience log made available to BBC staff across the Corporation.

Thanks again for contacting us.

Kind regards

BBC Complaints”

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82 Responses to The BBC explains its position on measurement units

  1. The Glob says:

    @kPa – Good questions. It is a long time ago now since I went to primary school (from the mid-1980s to 1992), I definitely remember only being exposed to SI units (or rather a subset of them) as part of practical exercises, as well as pen-and-paper. We did have lessons and exercises where we had to measure things using rulers and other instruments, definitely all using SI units only. There was no Imperial when I was at primary school.

    I don’t remember the exact details of what we did in our lessons back then, but I do remember that we encountered for example, centimetres, metres, grams, and millilitres (maybe millimetres, kilograms, and litres too but I am not sure) – I clearly remember us having to measure those in the practical exercises. As for the others I am not sure but I think we encountered millimetres, kilograms, litres, and kilometres in pen-and-paper exercises at primary school too.

    I don’t remember there being any formal teaching of SI as a subject in itself at primary school, it would have just been as measurement I think. So we were not taught what the prefixes kilo-, mega-, milli-, centi-, micro- etc. meant. The SI we learnt at primary at school was pretty much by contact with the units we encountered as you say, based on the practical as well as pen-and-paper exercises.

    We did have to write the correct unit symbol whenever measurement exercises appeared, but I don’t remember if we received an explanation of why, nor was it formally taught as such.

  2. Wild Bill says:

    My son is in his last year at primary school, so I asked him about this. He agrees broadly with what the posters above had said: they do *some* hands on measuring (but not lots) and some pencil and paper exercises – one where they were given a sketch map of some roads with dimensions in inappropriate metric measures (like distance to next town in metres, width of road in cm or mm) and expected to convert the units to more appropriate ones for the scale involved (distance to next town in km etc).

    So it was just a “move the decimal point and change prefixes to compensate” exercise, but sensible enough, considering it was really just part of learning about the decimal place-value counting system we all use. When units were involved, they were all metric.

    I asked if the alien distances on roadsigns messed him up, but he said no, because he didn’t pay much attention to them. Speed limit signs on the other hand have meant that he’s way more familiar with MPH than with km/h – no surprise there.

    He and his friends at playtime can occasionally be overheard using estimated measurements, and it’s all in metric. Stuff like “move back a bit Jack – another three metres eh?”. But I know that several of the boys have builders, engineers or medics for parents, and they (like I) use metric 100% at home. So the results might be a bit skewed.

    At one point my son was found to be the only kid in the class who knew what he weighed in kg (the kids from the other metric-friendly families were in a different class otherwise all three or four of them would have known).

  3. philh says:

    “You mention road signs as an example. I wonder though how much of an influence they really are. Are there that many signs and do people pay a huge amount of attention to them? Do people spend a lot of time looking at signs just to satisfy an imperial itch?”

    Don’t forget speed limits. They are mostly unsigned but all are in “mph”. Without metric on roads the kilometre is scarcely used and the mile persists generally in other areas of application besides transport. It would be quite a significant step forward if Britain were to metricate road signs.

  4. Ezra Steinberg says:

    My correspondent in Ireland (Republic) told me not too long ago that he noticed a definite shift there over the years to using metric in everyday conversation once the speed limit signs there were converted.

    Note that distance signs were converted gradually as old signs needed replacing (which the UK could do as well starting today), but that the “all at once” conversion of speed limit signs did seem to serve as a “tipping point” for the man / woman in the street in terms of their everyday usage of metric.

    Note that speed limit signs in Ireland show km/h below the actual number, so this reinforces the “metricness” of the sign (and makes perfectly good sense for safety’s sake since Ireland shares a land border with a country that has speed limit signs in miles per hour). Just like Wild Bill’s son most people of all ages pay attention to those signs. Converting those signs in the UK the same way Ireland did would almost certainly be a similar tipping point towards the disappearance of Imperial units.

  5. Ezra Steinberg says:

    I might add (since I live so close to the Canadian border) that one of the reasons Canadians typically express distances in kilometers is that they converted their road signs decades ago. Along with the sign changes came odometers and speedometers in metric only (because of metric speed limits) and maps in metric only (because of metric distance signs).

    I think it also noteworthy that Canadians are quite comfortable using degrees Celsius and have no understanding of Fahrenheit despite the fact that most Canadians live within 100 km of the US border and all US radio and TV broadcasts use only Imperial. This is because the Canadian Broadcasting Corporation has been using Celsius only (along with metric-only units for all aspects of their weather reports) for decades as well. This, along with a generally favorable attitude towards metric, has moved all Canadian media (radio, newspapers, and all privately owned media) to use metric only also.

    In sum, the argument seems quite compelling that converting road signs and having all BBC outlets use metric exclusively (to cite two specific changes) would create the aforementioned tipping point, especially (I’d imagine) for the younger folks who have little real understanding of Imperial any more.

  6. Wild Bill says:

    Back to school for a moment, I wonder if the very simplicity of metric has caused its teaching at (primary) school to be weakened? Back in the day, you could expect to ask 10yr olds to work out the area (in square yards) of a room 7ft 6in by 12ft 9in and it would be a genuine challenge, bringing into play quite a few arithmetic principles. But after the 1970′s the teachers probably found that asking the kids how many square metres there are in a room 3.2m by 5.6m is just *too trivial*.

    And so, they’ve moved to getting the kids to manipulate the S.I. prefixes as a way of making it a bit harder. But it still isn’t exactly hard. Maybe all this has caused weights and measures to lose the place they once had in the classroom.

    I would think that the “missing link” in schools at the moment might be that they need to concentrate more on getting the youngsters to do more in the way of real hands-on measurement of things. Like: with only a 30cm school ruler and a ball of string, what’s the area of the school yard in hectares? How heavy is this egg, when the only equipment you’ve got is a 1 metre rule and a 1kg bag of sugar and some sewing thread?

    And best fun of all on a rainy day: measure the area of the school yard *without going outside*!

  7. Peter Barber says:


    I know you were asking The Glob (!!) about his/her experience in primary school, but I too want to say that in primary school, metric was used exclusively. Admittedly I don’t have perfect recall of maths and science lessons from (state) primary school, but my recollection is supported by a couple of surviving exercise books from that distant era (the late seventies and early eighties), which contain absolutely no mention of imperial measurements.

    Re. parental influence, I do remember my parents being careful to stick to metric if I was showing them homework/doing baking/”helping” with DiY etc., even though they did (and still do) use imperial-based colloquialisms. (In fact my mum uses metric measurements even in that bastion of imperial, the allotment!) I must ask them when I next speak to them why they were keen on metric way back then…

  8. Peter Barber says:

    Re. speeds and distances in everyday speech,

    A common complaint I’ve heard or read against metric is that saying the unit names (especially with prefixes) is too cumbersome. Except, of course, that in colloquial speech you now hear people talking about distances or speeds in “kays” (i.e. kilometres or km/h) – for instance someone on Radio 4 a few days ago was talking about her journey by bike from the lowest to the highest accessible land surface on Earth, and she was consistently using this abbreviation for distances. And I believe she is in her fifties, so probably not metrically “indoctrinated” at school!

    And the great thing about the metric system is that because there is only one unit for length, it’s usually bloody obvious from the context whether someone means km or km/h – so not cumbersome at all! :-)

  9. philh says:

    @Wild Bill
    “Back to school for a moment, I wonder if the very simplicity of metric has caused its teaching at (primary) school to be weakened? Back in the day, you could expect to ask 10yr olds to work out the area (in square yards) of a room 7ft 6in by 12ft 9in and it would be a genuine challenge, bringing into play quite a few arithmetic principles.”

    It would be a fairly bright 10 year old who could cope with that.

    “But after the 1970?s the teachers probably found that asking the kids how many square metres there are in a room 3.2m by 5.6m is just *too trivial*.”

    Learning and applying the formula for the area of a rectangle is level 5 in the National Curriculum (there are 8 levels for the whole 11 year curriculum up to GCSE – ages 5 – 16).

    What matters is that kids understand how area is measured and why the formula works. There is plenty of scope for exercising their minds and practising their skills with more complex shapes involving a greater number of calculation steps.

    The trouble with practising area calculations in imperial is that, whilst it may involve extra arithmetic and hence more practice, it tends to distract from the real goal. They would learn more about coping with awkward measurement units than working with problems involving area.

  10. michduncg says:

    Back to the BBC – an interesting aspect to their use of metric units can sometimes be seen in their game shows. Last Saturday, Sept 24th on their ‘Secret Fortune’ show at 8pm is a good case in point.

    The format of the show is fairly simple – a pair of contestants are given a list of 4 items and they have to eliminate the 3 ‘smallest’ of the 4, leaving the correct answer.

    In this particular episode, 4 bridges were listed – The Golden Gate, Forth Road Bridge, Humber Bridge and Sydney Harbour bridge. When revealing the right answer in the end (The Golden Gate Bridge), the length of all four bridges were shown in metres.

    The final question in this episode asked the question ‘Which of the Imperial Units is the smallest’ – They included the fathom, the league, the chain and the mile. The contestant confessed to not knowing any of these units really (they were pretty young) and guessed at the league. This was incorrect and so their prize fund dropped £10,000. Afterwards, the correct answer was revealed as the fathom – but all of the units were shown on the screen, again, defined in metres.

    So, the BBC seems happy to use metric in quiz programmes, and it is good that they take this stance. The lack of knowledge of imperial units was also encouraging to me – people often claim that we are not a metric country, but what this shows is that people we are completely ignorant of the majority of Imperial measures – feet, inches, lbs and stone and miles. But these are a fraction of the old system, and do not form a workable system.

  11. Wild Bill says:

    Re Peter Barber above:
    I’ve always used “kays” to mean km (and km/h). Likewise I use “kilos” to abbreviate kilograms. I think everyone does in the english-speaking world apart from the US military who seem to use “klicks” where we might use “kays”. Or is that an urban legend??

  12. John Steele says:

    @Wild Bill

    The US military (mostly the army) says klicks. Runners say kay, and races are commonly described in kilometers, but using the incorrect symbol “K” as “I ran a 5K” which is obviously where the use of kay came from. (I suppress my desire to say “I hope you ran really fast because that’s damn cold.”)

    In a sentence providing sufficient context, I think most Americans would understand either klick or kay as kilometer even if they are a little hazy on how long a kilometer is. Ditto kilo for kilogram.

  13. Ken Cooper says:

    Around here, the most common usage would be “Kays” for distances and “Klicks” for speeds, but they are often interchanged.

  14. Wild Bill says:

    Thank you John Steele and Ken Cooper for the ‘klicks’ confirmation.

    As you say about races, a “10K” might be used to describe a race, but I don’t get het up about the capital “k”, nor the missing “m”. rather tend to think of “a 10K” as more like the name of a type of race, a name that hints at its length but stops a bit short of being technically accurate. It’s almost like I’m OK with the capital “k” because it’s capitalised because it’s used as a proper noun.

    I was at a “10K” recently where the intermediate distance boards had been printed up to say “1KM”, “2KMS”, “3KMS” etc, and I complained about that. I think the country’s children deserve to see better examples of distance markers done properly before they lose marks by copying such poor usage in their GCSE’s.

  15. Wild Bill says:

    BTW: Game shows.
    Anyone seen the excruciatingly bad (IMHO) “71 degrees North”? Seems like the whole thing is metric only, and that’s on ITV!

    I spotted a clip from some fake reality-TV thing called “The Only Way is Essex” where a guy was complaining that he’d have to go to “Weightwatchers” because he was XXX kg and overweight. I can’t remember what the “XXX” was, I was too astounded that he’d weighed himself in kg in the first place!

  16. kPa says:

    The term klick is common in usage in the US military and means 1 km.

    One explanation for its origin:

    A click is the full movement of an L1A1 gas regulator. Infantry navigate by bearing (compass) and distance (pacing)(pre GPS that is). The pacing was kept by one or two nominated soldiers (normal one of the rifles). They would count in lots of 100 metres (about 110 paces on the flat, 100 down hill and 120 uphill). The soldier would keep track of the ’100 metres’ by moving the gas regulator one mark. After a 100 x 10 the counter would get the attention of the sect comd by hand signals and signal the a 1000 metres had been travelled by lifting the rifle and obviously rewinding the gas reg with a movement of the thumb. The gas reg would come to a stop with an audible ‘click’. Hence 1 click = 10 x 100 metre = 1000 metre = 1 kilometre = 1 click. (aka 1 kay) I think you’ll find that the ‘click’ colloquial moved into American mil language from the Australians during Viet Nam.

  17. Michael Glass says:

    I doubt that the “click” for km came from Australia. Firstly, we say Ks instead of kilometres in informal speech. Secondly, Australian troops got out of Vietnam after the election of a Labor government in December 1972, while our road signs weren’t converted to metric until July 1974 so the timing doesn’t appear to be right.

  18. michduncg says:

    I have always assumed ‘klick’ was Australian in origin – I assumed it was just a condensed term for kilometre and may have been used to try and make the new metric measures an acceptable part of daily language by giving them slang names ‘klicks’ and ‘kays’.

    However – there is a wikipedia article which offers similar explanations and links to the US Military. It attributes the US Military use to the troops serving in Europe rather than Vietnam.

    Whatever the history is, I am glad these terms are coming to everyday use. We need people to be happy using metric and while ‘klicks’ and ‘ks’ may offend I think its a shoe in for the km!

  19. John Steele says:

    I have no opinion on where “klick” came from, but your military was likely using kilometers before your civilian population.

    We (the US) were using the Military Grid Reference System during the Vietnam Way as evidenced by some old maps on the web. MGRS is based on the Universal Transverse Mercator projection (except in polar regions), and is in meters. However, coordinates are within 100 km squares (very similar to Ordnance Survey), but a different sequence of assigning two letter codes to the 100 km tiles, that can be extended to the whole world with the addition of UTM zone and latitude band.

    Some further Googling indicates that MGRS was jointly developed by the UK and US from 1945-1949 as a result of interoperability issues in WWII, and that the US has used it in combat ever since. It contains some obvious concessions to European allies around and north of Norway, and we likely brokered an agreement with all of our allies to use it. Based on the above dates, that would be well in advance of civilian metrication efforts in Australia, Canada, US, UK, and other English-speaking countries.

  20. philh says:

    I first became of aware of “click” when watching an American war film set in Vietnam or some other post WWII conflict. It was used constantly right throughout the dialogue.
    At the time I assumed it was a contraction for kilometre but it now seems from comments above it has a more subtle origin.

    Whatever its true history I imagine it is easier to pronounce with a mouth full of gum :-)
    (all the soldiers were chewing it at the time).

  21. M says:

    The UK National Grid is also based on 100-km squares, at its 2-letter coordinate scale.

    However, the decision to adopt the metre as the unit of measurement for UK mapping was announced as far back as 1938 by the Davidson Committee – that apparently predates the US military’s decision by a few years.

  22. Martin Vlietstra says:

    I use kilometres frequently when driving on British motorways – driver location signs (the blue signs at 500 metre intervals on the sides of the motorways) give distances in kilometres. Prior to making the journey though I have to consult Wikipedia to relate distances to junction number.

  23. John Steele says:

    Another interesting BBC story and conversions. This one is about a pregnant woman who ran in the Chicago marathon and gave birth later that day:

    Two snippets that relate to conversion and the BBC:
    ‘Mrs Miller, who was nearly 39 weeks pregnant, said “it was the longest day of my life”. She gave birth to a healthy 7.7lb (3.5kg) girl, June.’
    We weigh meat that way, babies we weigh in pounds and ounces. The Washington Post reports the baby as 7 lb 13 oz, the odd 13 oz actually being about 0.8 lb. If WaPo is correct, the 3.5 kg may also be rounded down somewhat.

    “Because she half-walked the race, she finished the 26.2 mile (42.16km) course in 6:25 – slower than her usual pace.” Doesn’t everyone know that all modern marathons are officially 42.195 km long? Actually, they are nominally measured 0.1% long and the course measurer has to show his baseline is less than 0.1% in error to ensure a nominal tolerance of -0.0%, +0.2%.

    Interesting that they can’t get the imperial quite right either.

  24. John Steele says:

    Another BBC marathon error:
    Although it is an older article, they linked to it in their coverage of the New York City marathon. It is about the possibility of an “under two hours” marathon, presumable 1:59:59 or better.

    They again refer to the length of 26.2 mi, apparently unaware that this leaves one about 99 ft short of the finish line, as the 1908 marathon was 26 mi 385 yd, and this was metricated to 42.195 km. Since they run a short marathon, they can run slow. Their computation of a 4:35 average mile is slightly off, a 4:34.34 mile would be required. (An average speed of 21.1 km/h is required)

  25. kPa says:

    Will British people ever think in metric?

    By Jon Kelly BBC News Magazine

  26. Ronnie Cohen says:

    One thing that the BBC should understand is that familiarity with measurement units comes with usage. If the BBC still feels that it is still facing problems with public understanding of metric units, the BBC can encourage its viewers and listeners to visit the Think Metric website, which is run by UKMA. Its home page is The Think Metric website relates metric measurements to real-world objects and avoids imperial conversions.

    As an example of my point about familiarity, weather reports now predominantly use degrees Celsius. Fahrenheit has almost disappeared from weather reports. Metric units are now used throughout the retail trade except for a couple of minor exceptions (e.g. draught beer and cider and bottled milk). It seems that most people have adapted and have no problems with weather reports or retail supplies.

  27. Ezra Steinberg says:

    Ronnie Cohen makes a good point. Usage begets familiarity and comfort which begets more usage.

    It seems pretty clear that the UK has past the tipping point for metric usage and is now simply being hobbled by Imperial road signs and the continued usage of Imperial on radio and TV (other than the BBC in the main) and most newspapers.

    If the government were far-sighted and willing to convert road signs, allow the sale of beer in metric glasses, and quietly encourage their friends in the media to use metric rather than Imperial, I’d wager nearly all signs of Imperial would disappear from the UK in a few short years (aside from American TV programs and films shown in Britain).

  28. John Frewen-Lord says:

    I would agree with what Ezra said. At Chistmas, I gave my cousin’s husband (professional, early 60s), a small hand held GPS device that he could use to measure his runs (he is an active runner, and has competed in some marathons). It defaulted to metres and km, and when I mentioned that he could change it to imperial units, he said no, metric was just fine.

    Last week, in a local Tesco (in N E Lincolnshire), an older man, looking very much like a grizzled retired fisherman, but definitely not what would you call educated judging by his appearance, said to the assistant behind the deli counter: “Give me 200 grams of that there ‘am. An’ yer can add ‘alf a kilo of that there sausage meat while yer’re abo’t it.”

    I have to say that I was visibly shocked – to the point that my other half grabbed my arm and reprimanded me for staring at the man.

    But then my delight in this show of metric usage was shattered at a seminar I attended at Heathrow airport. The presenter – a woman in her 50s – resolutely used imperial measures, even to the point that when she enlisted her kids to help her make some props, she was very specific in asking them to use only imperial measurements. I felt sad for her kids.

    Overall though, I see more and more metric being used very day – and, as in the case of the ‘retired fisherman’, by the most unlikely of people. Past the tipping point? Possibly, but still some way to go.

  29. Andrew says:

    It’s now 2015, and I’m watching Pompeii: Mystery of the people frozen in time.
    All measurements are in km with no translation.
    The BBC are deceiving in their reply. The BBC are simply trying to Europeanise the UK. We already know they’re biased towards pro-European political parties

  30. wilfred says:

    From 1974 onwards, all STEM subjects (science, technology, engineering and mathematics) have been taught in the UK using metric units, from primary school right through to university and beyond. Science helps us work out what happened in Pompei in AD 79, so why not use metric units? Miles really belong on road traffic signs.
    It might have been more appropriate for the BBC to use the Roman mile of 5000 Roman feet (about 1480 metres or 4860 Imperial feet) but at the risk of leaving us thoroughly confused. As the Romans knew and we seem to have forgotten, a country needs one system of measurement, not two or three.

  31. Charlie says:

    @ Andrew

    I am sympathetic to using miles as a “translation” – as you put it – of kilometres all the time that road signs remain in miles; I am willing to accept that, for the time being, a distance given in miles is more likely to be more widely understood than one given in kilometres in the UK; for me there’s no reason not to include both (until those wretched road signs are changed).
    Alas, the metric system is international – not European. So this process of europeanisation you speak of is probably better described as globalisation – the process through which the UK realises that this isn’t the 1800s anymore, and we are actually working with most of the rest of the world rather than against it, and a single system of measurements is in the global interest.

  32. Michael G says:

    Well I am just settling down to watch the BBC coverage of the Six Nations, England v Wales and I am horrified that the BBC is going all imperial in the coverage. They are using yards for the pitch measurements, and stones for weights. I am pretty sure that Rugby is a metric sport as far as pitch markings go, and I know that most athletes use kg to measure their weight. What a mess.

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