Why can’t weights and measures be left to the free market?

There have been recent reports in the press a butcher in Devon has started to sell meat in pounds and ounces after the UK had voted to leave the EU in a national referendum on 23 June 2016. This butcher is now giving customers the choice to buy meat in pounds and ounces or in grams and kilograms.

According to newspaper reports, this measure has proven to be popular with customers and has gained a lot of support from the general public. This story has appeared in the Daily Express and The Sun, as you would expect. Apparently, some people think that it is a good idea to give shops and market traders the freedom to choose metric or imperial units to sell their products.

The problem with the use of mixed measures can be shown by comparing the following lists:

Mixed Measures Single Measure
  • Apples: 48p/lb
  • Pears: 95p/kg
  • Oranges: 80p/kg
  • Bananas: 35p/lb
  • Peaches: 32p/lb
  • Tomatoes: 60p/kg
  • Cucumbers: 30p/lb
  • Potatoes: 28p/lb
  • Onions: 70p/kg
  • Leeks: 80p/kg
  • Apples: £1.05/kg
  • Pears: 95p/kg
  • Oranges: 80p/kg
  • Bananas: 77p/kg
  • Peaches: 70p/kg
  • Tomatoes: 60p/kg
  • Cucmbers: 66p/kg
  • Potatoes: 60p/kg
  • Onions: 70p/kg
  • Leeks: 80p/kg

Which list is easier to compare? I give you no prizes for guessing the answer.

If traders were given the freedom to use whatever units they like, we could also end up with petrol priced in litres and gallons, fridges advertised with capacity in litres and cubic feet, electrical products described with a mixture of watts and horsepower, table sizes given in feet and metres, land areas advertised in acres and hectares, temperatures expressed in Celsius and Fahrenheit, etc. This makes comparisons needlessly awkward. We all need a single system of weights and measures that we can all understand and use. We do not need two systems.

These days, the major British supermarkets are almost exclusively metric. Most show unit pricing per kilogram, per 100 grams, per litre and per 100 millilitre. When we go to the supermarket, we take it for granted that we can quickly and easily compare prices between different products because they use a single, simple and consistent measurement system. This system is the metric system. Imagine how awkward that would be if supermarkets used incompatible measurement systems with awkward conversion factors.

The problem of using multiple measurement systems was considered by a parliamentary Select Committee on Weights and Measures in 1862. They found this situation unacceptable. Here is a quote for their report:

“The silent influence of usage has baffled the decrees of legislation; and we are still far distant from the uniformity at which we have so often, yet so vainly, aimed. Omitting many specific anomalies, we have no less than ten different systems of Weights and Measures, most of them established by law. Our neighbours, the French, and many other nations, have only one, founded on the mètre, which is a near approximation to the English yard.”

The report lists ten different measurement systems that were in use in the UK at the time:

  1. Grains, computed decimally, used for scientific purposes.
  2. Troy weight.
  3. Troy ounce, with decimal multiples and divisions, called bullion weights.
  4. Bankers’ weights, to weigh 10, 20, 30, 50, 100 and 200 sovereigns.
  5. Apothecaries weight.
  6. Diamond weights and pearl weights, including carats.
  7. Avoirdupois weight.
  8. Weights for hay and straw.
  9. Wool weight, using as factors, 2, 3, 7, 13, and their multiples.
  10. Decimal coal weights.

The report goes on to describe more measurement systems that were also in use in 1862. Alas, the problems with the use of multiple measurement systems has long been forgotten. Weights and measures are regulated by law to prevent the chaos that arises from the use of multiple systems of weights and measures and to ensure uniformity and common standards of weights and measures. This is the case, not only in the UK, but in most other countries.

This was no doubt in the mind of England’s King Edgar the Peaceful when he enacted in AD 965 a law “that only one weight and one measure should pass throughout the king’s dominions”, a principle that some, including that Devon butcher, have preferred to overlook in the 21st century.

10 thoughts on “Why can’t weights and measures be left to the free market?”

  1. “If traders were given the freedom to use whatever units they like, we could also end up with ……”

    This is exactly what historical trading was like. Even as far as traders creating their own definitions for weighs and measures that suited them at the expense of the consumer. It is for these reasons that weights and measures laws were enacted and enforced. Those who insist on this freedom do so in order to have the advantage over the consumer often by deceptive means. Even to the point of having non-calibrated scales that could be off in favour of the shop.

    Those who feel comfortable with pounds are not deprived. I believe in France and other parts of Europe the equivalent of the pound is still referenced. I don’t know by how much, but this is not a problem. Shops have only metric scales and pricing is fully metric only. Yet for those asking for a pound, what is done is simple. The clerk converts pound to 500 g and weighs out that amount on the scale. The customer knows what he/she is getting and is content.

    This can and should happen in the UK. A customer asks for a pound, has 500 g weighed out for them and pays 5 x the 100 g price. Where is the problem?

    I’m not sure how much the media story about selling in pounds is hype. I’m sure nothing changed. The scale is still in kilograms and as before they had dual pricing. Those asking for pounds just had them weighed out in grams. Nothing has changed .

    Obviously they also have customers asking for grams and a change to complete imperial would isolate them. They are hiding behind their statement that they need to ask Trading Standards for their advice. I’m can tell you what the Trading standards advice will be. 1.) You have to have certified metric scales. 2.) You have to advertise in metric and if you choose, you can add supplemental imperial in smaller font.

    Of course some pricing labels or boards don’t have room for all of the supplemental gibberish and time and money spent adding what is not needed only increases costs. Of course when they they do supplemental additions the costs they pass on are higher than the cost of the supplemental gibberish.

    I’m not exactly sure what this shop did differently than before, but whether they did nothing different or something minor, it didn’t hurt to get the free advertisements for others to come to their shops. Once the publicity dies down (I’m sure it has by now) those extra customers they got will slowly disappear and they will be no better of for it. The metric only supermarkets outsell these shops due to being able to sell at lower costs. I wonder how many of these shops struggle to stay in business and how many eventually give up. Every picture I’ve seen of these shops, they seem to be empty and lacking customers.


  2. It is important that Trading Standard Officers (TSOs) are reminded, even if ever so gently, that the UK has passed legislation permitting only metric units to be used for almost all trading, regardless of what (some – far from all) customers would like to see. Even before AD965, and even going back to Roman times, some form of standardised system of weights and measures was considered desirable and even implemented. It is no different today.

    Someone once said that no country needs more than one set of measurement units. In this day and age, where 96% of the world’s population knows only the metric system, and recognising that the UK must now engage with that population without the benefit of being in the EU, we had better be very familiar with the metric system. And the way to do that is outlaw any other units of measure in all trade and business. The Leavers said we can now trade with the world! Well, indeed we can, but only if we speak their language of measurement very fluently.


  3. To paraphrase the inscription on the ring (from Lord of the Rings):

    * Three measures for the Elven-kings under the sky,
    * Seven for the Dwarf-lords in their halls of stone,
    * Nine for Mortal Men doomed to die,
    * One for the Lord of Light on his splendiferous throne.
    * One SI to serve them all. One SI to free them.
    * One SI to bring them all and in the light bind them.

    Huzzah! 🙂


  4. There is an inconsistency here – perhaps even deliberate misrepresentation – of what “one weight and measure” means. As with Richard I’s 1197 decree that there should only be one weight and one measure throughout the kingdom or Clause 35 of the Magna Carta of 1215 which demands one weight and one measure for each of several different commodities, Edgar’s law is also simply mandating a single central standard for length and another for weight. None of those common-sense ideals prohibit the use of named unit multiples or submultiples .

    Given that all current metric and imperial units are defined in terms of the same single central international standard, the mandate is fully complied with. The pound and the kilogram share the “one weight” definition and the yard and the metre share the “one measure” definition. We are fully compliant.

    The facts that a metre is defined as the distance travelled by light in 1/299,792,458th of a second and a yard as exactly 0.9144 metres means they are of “one measure” as much as the metre and the centimetre are or the metre and the kilometre. And the facts that a kilogram is defined as the mass of a specific lump of platinum alloy kept in Paris and a pound as exactly 0.45359237 kilograms means they are of “one weight” as much as the kilogram and the gram or the kilogram and the milligram are.

    I’m sure we are not suggesting that the comply with the “single measure” and “single weight” ideals we are saying that all named multiple and submultiple units should be dropped – are we?


  5. Principal local authorities are fully stretched coping with the funding demands of adult social care, the housing crisis and central government support grant cuts.
    Very few will want to waste scarce resources on backing unpopular hobby horses such as the compulsory metrication of the UK by prosecuting traders. They have far more important matters to deal with.


  6. It posting on reddit/metric has made it clear that imperial only scales as well as dual (with switches) are becoming difficult to come by. As these scales wear out, there are fewer and fewer of them for illegal shops purchase.

    I suspected this, but had no proof. This is why the TSO doesn’t bother going after illegal scales. They know that in time the pound scales will break and need to be replaced and the only scales available to replace them with are the metric only type.

    The Luddites are in a panic over this and have entertained the idea of smuggling pound scales from the US. They fear though the consequences of confiscation and fines and possibly something much worse if they try.

    The TSO might look the other way when using an aging uncertified scale but I’m sure they will confiscate and prosecute anyone using a modern scale not kilograms only.


  7. In the eighteenth century, France had all but left weights and measures to the free Market. Ken Alder, in his book, “The Measure of all things” wrote “One Englishman, travelling through France on the eve of the Revolution, found the diversity there a torment. ‘[I]n France,’ he complained, ‘the infinite perplexities of the measures exceeds all comprehension. They differ, not only in every province, but in every district and almost every town …’. Contemporaries estimated that under the cover of some eight hundred names, ancient regime France contained a staggering 250,000 units of weights and measures!”
    This is of course an extreme case, but does illustrate what can happen if the free market is allowed too free a reign. For a free market to work properly, freedom of price is essential, but if there is to be freedom of price, a level playing field can only be maintained if there exists means of comparing prices in a meaningful manner. That is the reason why medieval English Kings demanded (or were forced by their barons to demand) that there be one system of measure throughout the kingdom. At the present moment in time that system of measure in the United Kingdom is the metric system.


  8. @Charlie P:

    I propose the following test for your `singular’ theory; next time you submit a planning application, dimension the drawings in imperial yards and scale them in multiples of 12 on princess sized paper. If they reject it out-of-hand within seconds of banking your fee citing incomprehensibility, appeal on the grounds that `they are just [sub-]multiples of 0.9144 m and can be enlarged/ reduced with a photocopier’ and offer to convert the measurements into wavelengths of krypton-86 for clarity.

    p.s. Sèvres != Paris.


    Some `principal local authorities’ are now fretting about losing their EU subsidies, much to the bemusement of the UK government now that many of the leaders of Project Fantasy have become uncontactable. But trading standards are somewhat independent of this compared to the more discretionary services.

    As John Frewen-Lord and others have pointed out above, metric alone is compulsory for almost all purposes and has been for some time now. If you believe that trading standards (and others) are too stretched to enforce compliance with the existing law, then you can bet they will baulk at de jure attempts to re-introduce archaic measures alongside or in place of the metric system. As for de facto attempts, those are nice little earners for TPTB…


  9. In the case of retailing, commercial considerations mean that the mug-punter is more likely to be impressed by the relatively larger figure, logic not withstanding. Thus litre sounds far more impressive for the car boot volume than say cubic metres or even cubic feet. Miles per gallon sounds a lot better than kilometres per litre. Fruit and vegetables priced per pound show a lower sticker price than priced per kilogramme.
    UK Trash Culture, where education and learning are belittled as elitist. Seriously, what would you do with it? Besides hate it and leave it. Education … gimme me a break.
    Jack, the Japan Alps Brit
    Thirty-three years and counting


  10. At the risk of repeating points already made.
    Go into any supermarket nowadays and take a look at the fresh fruit and veg sections. You’ll see a variety if different methods of pricing. Some per pack, some each and some per unit weight. I’ve seen all three for the same type of produce.
    Impossible to compare prices that way!
    That’s the sort of thing traders will do if they can get away with it, as sadly in these cases they do.
    As for the unit of weight, it has to be standardised and so there cannot be infinitely many of them, so there has to be a selected list of allowed units. Again the free market would not do this for themselves.
    Just consider clothes sizes where there are no enforceable standards. How often have you bought or tried on a garment which sometimes fit and sometimes doesn’t from different shops even though they are supposed to be the same size?


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