Myths about metric

The drawn-out process of metrication in the United Kingdom has encouraged misconceptions and active disinformation about the metric system. This page separates fact from fiction.

1. The UK is being forced to adopt the metric system by the EU
2. The EU has criminalised the use of imperial units
3. Other EU countries do not criminalise the use of imperial units
4. A Sunderland market trader was prosecuted for selling a pound of bananas
5. Consumers and retailers should be free to use the units they prefer
6. The case of the so-called "metric martyrs" is about "freedom of commercial speech"
7. Metrication costs money
8. The USA has not gone metric
9. Even metric nations use non-metric units
10. Road signs could only be converted overnight
11. The British are incapable of thinking in terms of kilograms
12. If Britain adopts metric we will no longer be able to say 'pound of flesh'
13. Pounds and ounces are British, kilograms are foreign
14. 3.5 in floppy disks aren't metric
15. The new regulations mean A4 paper is banned
16. Centimetres are not valid within SI
17. Metrication means the compulsory use of decimal numbers

The approximate history is as follows:

It has been a criminal offence to use the peck and bushel since 1968. Other units whose use has been a criminal offence for some years include the stone and hundredweight. Penalties are set by national governments.

On the wider issue of denying freedom of choice, weights and measures legislation is there to protect the public, by ensuring that the standards used for measuring equipment are maintained, and that traders are providing honest and open information to the public. Trading Standards Officers protect the public against unscrupulous traders. To permit traders and public to pick and choose which units they want to use would lead to anarchy, and the sort of confusion that anti-metric supporters claim to be against. There was no outcry by such people when a UK publican was fined by Trading Standards for selling beer in metric measures! Nor were there any complaints when it became illegal to sell by the stone several years ago.

It is up to individual nations how transgressions of national laws are penalized. EU Directives were established to harmonize units of measurements across the member states in order to facilitate trade. The actual legislation to enact these requirements is the responsibilty of each member state, as are the penalties for breaches. The penalties within the UK have not changed substantially since the 1963 Weights & Measures Act, and the most severe are reserved for offenders who persistently give misleading information. All that has changed is the list of permitted units. So someone persistently advertising by the bushel or peck could have been fined after 1968, even before the 1995 metrication legislation was enacted.

Further afield, in New Zealand, breach of the regulations can result in a fine of up to NZ$5 000.

In order to ensure that the public gets accurately weighed goods, the type
of weighing machine at the point of sale must be approved and regularly
checked. It has always been the case that approved equipment only use units that are legal for trade. Since the year 2000 the units allowed for the sale of loose goods have been metric only. Prices of loose goods are also required to be labelled in metric. Imperial conversions are allowed in addition for assistance.

A customer is allowed to ask for loose goods by the pound but the shopkeeper
is required to weigh the goods using metric scales. In any case, most people
order bananas by the bunch rather than by the weight and the price of the
bunch is calculated from the weight and unit price.

The trader in question, Steve Thoburn, tragically died of a heart attack on 14 March 2004.

Consistent rules for pricing and measuring are fundamental to honest and fair trade.

A single approved system of units for weighing has been historically a key method to protect the consumer. Uniformity of measures is prescribed in both the Magna Carta and Act of Union between England and Scotland.

If shopkeepers are free to choose their units for pricing goods, price transparency is lost. How can anyone know whether a shop selling bananas at 45p/lb is more expensive than another selling at 92p/kg without using a calculator? Equally, if shopkeepers were able to choose any system with which to measure their goods, you would start seeing bushels, pecks and hogsheads.

The transition from using gallons to litres in filling stations, where price per unit is less because the unit is smaller happened smoothly almost overnight, while the transition from pounds to kilograms, where price per unit is more because the unit is larger, has met with resistance.

If unrestricted expression is allowed in trade, the consumer always suffers. This is why for example the degree of expression allowed by estate agents has been curbed.

Adopting the metric system does not stop the use linguistic expressions like "a pound of flesh" from being used. Indeed many cultures continue to use pre-metric units in everyday expressions.

This is a statement often used, but grossly exaggerated in many cases, and untrue in others. Whilst it is true that replacing or recalibrating equipment costs money, it has to be remembered that businesses write off equipment against tax over a given period. Also, equipment wears out, and competitive pressures mean that some equipment has to be replaced before it wears out, if the company is to remain competitive. In any case, dual pricing costs time and effort for the retail trade.

The excruciatingly slow pace of metrication in the UK (41 years and counting) exposes the desperate nature of such claims. In addition, claims of not being given enough warning must be regarded with suspicion (especially when voiced just a few months before new legislation), as the main EU directive behind the latest legislation appeared 17 years ago. Admittedly, the DTI has ducked its responsibility over giving widespread and timely publicity, and much of the press has given misleading information.

The experiences of companies who have metricated have shown that metrication can actually save money. British engineering companies, US car manufacturers, and even the US Government (who mandate that new federal buildings be designed in metric) have all found that fewer different stock items and ease of use can reduce costs. Prolonging the process adds to costs.

The vast majority of the world's population uses metric. The only nations other than the USA which remain officially non-metric are Liberia and Myanmar (Burma).

The population of the US is smaller than commonly perceived - approximately five times that of the UK. Thus 6.5% of the world's population of 6.3 billion people lives in officially non-metric countries - that is, 93.5% live in metric countries.

Although the USA has made only erratic progress towards metrication (like the UK), it has nonetheless advanced. Its wine and spirits industry made the change back in the 70s, the car industry went metric in the mid-80s (with considerable savings), and many goods are appearing in shops in rational metric sizes. Dual-labelling of goods is now mandatory for most products. The US is ahead of the UK in one significant area: that of road signs. They repealed the legislation which forbade metric units on signs over a decade ago, something which the UK has still to do. For more detail on practical examples of the changes happening in the USA see Jim Frysinger's Metric Methods site.

In any case, the 'customary' measures used in the US are not identical to imperial measures (for instance, gallons and fluid ounces), and the 'stone' is as unknown as the 'fortnight' in the US.

This warrants closer examination. In many cases, it is the historical dominance of the USA in particular fields that has forced the rest of the world to fall into line. Examples are:

• Computer screens (though European companies often include the centimetre size as well)
• Guns & ammunition - obviously these have to be mutually compatible, and become self-perpetuating
• Car wheels - the past dominance of the US car industry
• Plumbing fixtures - a few European countries use inch-based parts
• Aircaft heights and speeds, engine thrusts in pounds force - US industry dominance again

In other cases, names of non-SI units have been retained in a colloquial way. Many bear little or no relation to the 'imperial' units we have used in the UK, e.g. there have been many variants on how long a mile is. (Even within the British Isles the mile often varied by region). In other cases the terms are used as slang for actual metric units, e.g. the livre (pound) in France means 500 g.

It has been argued that these units are not permitted by the EC Directives. However, it is important to note that these terms do not have any legal standing. To say that we should not use legally-enforced metric units because of these uses is a non sequitur. This is like saying we should not use terms like 'quid', 'bob', 'fiver' (or 'buck' and 'penny' in the USA), because these have never been legal terms of currency. It is certainly nonsense that imperial units frozen in stock phrases like 'to give somebody an inch' are relevant to the debate.

The argument against a gradual replacement of road signs by the government is that it would be unsafe. Ireland successfully converted the majority of its distance signs over a period of years by replacing worn signs and installing new ones with km-only markings. Speed limit signs were then replaced over a period of a day or so in January 2005, which coincided with a general revision of national speed limits. An alternative strategy would be the Canadian one, where decals showing km and km/h were placed over signs on their Labour Day weekend.

The experience of Ireland's conversion has shown that there are no safety issues concerned with the metrication of road signs, provided that the transition is thoroughly planned and co-ordinated. It should also be noted that vehicles in the transport industry (both people and freight) have metric speedometers and odometers. If safety issues don't arise in an industry where public safety is regulated carefully, why should they for car drivers?

It's curious that opponents of metrication wish to insult the British people by implying that they cannot understand a simple system which the rest of the world uses daily. Any confusion is due solely to the lack of a good transition plan and the absence of an extensive public education programme.

• Most British people are familiar with a pack of sugar. It weighs one kilogram.

• In 1971, Britain successfully changed from £/s/d to decimal currency aided by a two-year public information campaign to every home.

• Britain has educated children for more than 30 years in the metric system but has given them little opportunity to practise it outside the school gate.

• Australia, New Zealand and South Africa, all countries with similar cultures to the UK, are able to think in terms of kilograms. Government-funded public education programmes assisted the people in these countries, unlike the UK.

It is nonsense to suggest that figures of speech have to change. References to pre-metric units survive in other languages. English-speaking countries like Australia and New Zealand did not change their language on adopting the metric system. With regard to Shakespeare's reference to Shylock's pound of flesh, remember that the pound used in Venice consisted of 12 Italian ounces! The Italian 'pound' in the figure of speech was never converted to 12 oz imperial.

Although the name 'imperial' refers to the 19th-century codifying of units in 1824, imperial units have their roots further back in time. Many so-called imperial units are based on Roman units imposed across Europe as part of their Empire. Thus although the word pound is linguistically related to the modern German Pfund and Dutch pond, the abbreviation 'lb' comes from libbra and the abbreviation 'oz' for ounce comes from onza. There are two variations on pounds and ounces in the imperial system: avoirdupois ('goods of weight') comes from the time in the 14th century when London merchants adopted a French approach to weighing; while troy measure is based on the system used in the town of Troyes in France. Thus, far from being truly British, pounds and ounces have their roots in Italy and France.

Metric units such as the kilogram, of course, have their origins in late 18th century France. However, since the Metre Convention of 1875, the development of the metric system has become a truly international effort. Britain has participated in the development of the metric system for over a century. So, just as telephone standards are subject to international agreement through the ITU (International Telecommunication Union), even though the telephone was originally developed by a Scotsman living in the USA, the metric system is subject to international agreement through the Metre Convention. The metric system is no more 'foreign' than the telephone system!

The standard defining these diskettes - ISO/IEC 9529-1 - defines their dimensions as 90.0 mm x 94.0 mm. Neither round metric measurement equals three-and-a-half inches.

Logical thinking really went out the window with whoever came up with this gem! The A4 paper standard is defined wholly in metric units.

This misunderstanding has its roots in the development of SI as a rational and coherent system of units and in the encouragement of best practice in engineering and science. For these purposes it is recommended that the use of multiples and sub-multiples of units be restricted to factors of 10³, e.g. μm, mm and m. So engineering drawings and building plans are labelled in millimetres only. Regardless of the system of units used, it is unwise to mix units (e.g. inches and feet).

Regrettably, our own British Standards Institution promulgated the idea that the centimetre was not an approved unit, and as a result, the millimetre has been used (often expressed in terms that indicate a totally unwarranted precision) for many consumer products where the centimetre would have yielded a much more 'user friendly' figure. Of course, anti-metric folks do not point out the error of such practice, instead seizing on it as proof of the unsuitability of SI for everyday use.

The metric system is predominantly decimal but uses other number systems where appropriate. For example there are 60 seconds in a minute.

This wacky myth is frankly an insult to the intelligence. Just because products are say weighed in grams or in cans measured in millilitres does not dictate how they are to be packaged. It is possible to buy eggs by the half dozen in France, buy a pack with 5 chicken breasts (600 grams), buy an 8-pack of Danish Carlsberg lager (500 ml cans), buy a pack of 12 Cumberland chipolata sausages (425 grams) or Ferrero Rocher chocolates in a pack of 16 in each case using metric weights and measures.