A UK metric time line from 1980

In June last year, we published a time line up to 1980 showing progress towards the adoption of a single, simple, logical and coherent measurement system in the British Isles. We now bring this story up to date.

1980 onwards
Manufacturing industry, which had been slow to adopt metric measures, now sees its export markets shrink as other countries of the former British Empire complete the metric transition. Although this is not the only factor contributing to Britain’s industrial decline, it is a significant one. Hard hit is the West Midlands, the birthplace of the industrial revolution.

On garage forecourts, pricing per litre is permitted. This had been requested by garage owners to enable an extension of the life of older pumps, many of which are limited to a maximum price of only £1.99 per unit. Equivalent prices per imperial gallon must be shown alongside the price per litre.

The Weights and Measures Act 1985 enables many imperial units to be dropped from use for retail sales by weight or measure. It also redefines the imperial gallon as 4.546 09 litres exactly. It does not cover goods and services sold by description, for example a “32 inch TV” or a “five foot Christmas tree”.

Foreign-owned manufacturing companies see the potential of the UK: located inside the EEC tariff wall, English speaking and possessing a skilled work force and a supply chain that is adapting to metric production. Nissan is among the first to become established, opening a pioneering car production plant in Sunderland.

Honda opens a factory in Swindon to build car engines.

Toyota opens a plant to build cars in Derby and Honda opens one in Swindon.
Metric units are substituted for, or permitted as alternatives to, imperial units in many regulations. As an example, domestic gas consumption can be charged by the kWh instead of by the therm.

The UK Hydrographic Office announces that it is able to provide data in digital format for those charts which show depths in metres.
Boeing cancels its project to build an ultra-high-capacity airliner (UHCA). This creates a gap in the market which is subsequently filled by the Airbus A380.

In July, regulations are laid before Parliament relating to metric units of measurement and their use for weights and measures and price marking purposes.
Retailers of carpets and floor coverings prepare, for the second and final time, to switch to pricing per square metre.
The last pumps at filling stations that are calibrated in gallons are converted to litres or replaced.
The Traffic Signs, Regulations and General Directions (TSRGD) 1994 allow but don’t require metric measurements on signs which impose height restrictions.
BMW acquires the Rover Group, including the Mini brand. It later switches production of the Mini from Longbridge to a rebuilt plant and new production line at Cowley, Oxford.

All imperial units cease to be primary measures, except for eleven units when these are used for specific purposes. Many familiar units, including the square foot, square yard, cubic foot, quart and gallon, though still able to be used, are no longer legally authorised.
In pubs, spirits must be served in metric quantities eg 25 mL, 35 mL.
On garage forecourts, equivalent pricing per gallon is no longer obligatory.
Regulations prescribe rational metric sizes for many pre-packed goods.
New gas and water meters show consumption in cubic metres, although some existing gas meters showing cubic feet may well survive until 2020.
Some non-SI units required by international treaties in air, sea and rail transport remain in use without time limit, for example the nautical mile, knot and foot (for altitude).
In July, the Department of Trade and Industry (DTI) publishes a report, “The adoption of the International System of Units as the primary system of measurement in the UK”.
The British Weights and Measures Association is re-launched “to protect and promote British weights and measures, and to oppose compulsory use of the metric system”.

Supermarkets, butchers, fishmongers, grocers, greengrocers and corner shops complete their preparations for the switch to weighing and pricing in metric.

The therm, fathom, gill and fluid ounce are no longer legally authorised.
Weighing for retail sale of ‘loose goods’, for example fruit, vegetables and cheese, using imperial measures is no longer permitted and metric prices must be displayed. Customers are still able to ask for pounds and ounces, and supplementary pricing in imperial is also allowed, so it is only traders that are affected. A few find difficulty weighing or pricing in metric.
Croydon Tramlink opens with metric speed limit signs.

A group is formed with the aim of removing road signs which it considers fall outside the traffic signs regulations because they show metric measures. It achieves publicity the following year after its founder is convicted of theft and criminal damage when about 40 signs are removed in Kent. The conviction for theft is overturned on appeal after the signs are recovered.
Four traders are convicted under the Weights and Measures Act or the Price Marking Order for failing to weigh goods in metric or to price goods in metric alongside imperial.

The four traders who were convicted in 2001 for failing to weigh or price goods in metric together with one other trader lose their appeal against their convictions.
The TSRGD 2002 allow but do not require metric measurements on signs which impose width restrictions.
The Government say changing road signs would be confusing for drivers who had not received a metric education at school, and use this as a reason for postponement.
The UK Metric Association (UKMA) is formed.

The DTI, the British Standards Institution and the Confederation of British Industry publish the “Final document” and “Implementation annex” of the National Standardisation Strategy Framework (NSSF) – a joint attempt to improve the UK’s economic performance by harmonising standards. UKMA considers that the NSSF misses the point – standards can only be harmonised if everyone uses the same measurement system. Its response, “A very British mess”, is published in 2004.
Driver location signs that complement distance marker posts are introduced experimentally on motorways and major highways.

One of the traders convicted in 2001 dies of a heart attack, becoming anti-metric campaigners’ first ‘metric martyr’.

Over a single week-end in January, the Republic of Ireland completes the metric conversion of its road signs by changing all speed limit signs – distance signs had been converted gradually over the previous decade. For the first time, the UK has a land border with a country that uses a different measurement system on its road traffic signs.
Prescribed quantities are abolished except for alcoholic drinks.
MG Rover Group, formerly British Leyland, goes into administration bringing an end to mass car production by British-owned manufacturers – with MG and the Austin, Morris and Wolseley brands becoming part of China’s SAIC.

The UK Department for Transport (DfT) publishes an estimate of the cost of converting road traffic signs for distance and speed. The estimate for speed limit signs is about 180 times the one prepared in 1970 – ‘gold plating’ is suspected.
UKMA publishes its report, “Metric signs ahead”, on the conversion of road signs, together with its estimate of £80 million (in contrast to the DfT’s £700 million).

In October, the Airbus A380 enters commercial service. Major structural sections of the Airbus are made in France, Germany, Spain and the UK (wings and engines) and then assembled in France.
In November, the Channel Tunnel Rail Link with metric distance and speed limit signs opens from the Channel Tunnel to St Pancras International.

Nic Davison is served with an infringement notice for selling draught beer by the litre at his Polish restaurant in Doncaster. He refuses to change, and eventually the case against him is dropped.
The National Weights and Measures Laboratory issues an “Update on metrication”, saying it is “keen to encourage [enforcement] action that is proportionate, consistent and in the public and consumer’s interest.” It adds, “Consistency of units allows customers to make value-for-money comparisons with similar goods on offer.”
Sales of canned and bottled beer exceed those of draught beer for the first time.
The European Parliament approves an amended measurement directive. The UK Government then claim credit for “saving the pint and the mile”.
The DfT sets up the Traffic Signs Policy Review, heralding it as the “the biggest review of British road signs for forty years.” The review runs from September 2008 to May 2011, but does not consider metrication policy and achieves little.

At the end of the year, the acre ceases to be a primary unit.

The use of supplementary indications is permitted indefinitely, as well as the use of six imperial units for specific purposes only:
* the mile, yard, foot and inch for road traffic signs, distance and speed,
* the pint for draught beer and cider, and doorstep milk, and
* the troy ounce for trading in precious metals.

The Traffic Signs (Amendment) Regulations and General Directions 2011 allow optional dual (metric and imperial) triangular signs warning of height or width restrictions, and require the internationally recognised symbol “t” for tonne to be used on new weight limit signs.

Preliminary results of the 2011 census show that a majority of the UK population has been taught using metric measures at school.
The London Olympics raise the profile of metric measures in millions of UK homes.

The Government admit that failure to convert road traffic signs may require changes to the school curriculum. Perhaps it realises that its argument about drivers needing to understand the units used on traffic signs is a two-edged sword.

As with the first part of the time line, we welcome readers’ suggestions for additions and amendments. These will be incorporated and the time line will then be posted on the UKMA web site. The first part including readers’ suggestions has now been uploaded and can be found at the time line page.

The time line shows that the UK’s metric transition falls into three phases:

In the first phase, between 1963 and 1979, there is initially widespread optimism among business leaders and politicians, with planning taking place during the late 1960s and a steady advance on voluntary conversion during the 1970s. But as new areas for voluntary action diminish and it becomes clear that compulsion will be necessary to achieve further progress, politicians’ nerve fails, and the changeover stalls.

In the second phase, between 1979 and 2008,  several years of inaction are followed by a flurry of activity from 1992 onwards as the necessary orders are approved by Parliament and some hard work is done. We then see growing public opposition, until in 2008 the politicians again signal a halt.

During current and final phase, whose duration is uncertain, it is likely that the use of imperial units will fade away, as has happened in many other countries around the world, possibly hastened by globalisation, and imperial road traffic signs will be seen as a costly and inconvenient anachronism and a national embarrassment.

In conclusion, we note that the winding down of the imperial system of measures in the UK has now taken longer than the winding down of the Empire that gave it its name!

(Editor: Thank you, Erithacus, for your suggested amendment and correction. These have now been incorporated into the article.)

10 thoughts on “A UK metric time line from 1980”

  1. Very interesting. However, we should not fool ourselves that there is an inevitable progression toward full metrication. The history since 2000 (when the sale of “loose goods” went metric) suggests that governments have effectively given up on the project and are not prepared to take on the opponents, especially in the right wing tabloids. It will require political courage and commitment (both conspicuously lacking in all political parties) and probably further legislation. It won’t just happen of its own accord.

    One or two detailed points:

    The DTI report “The adoption of the International System of Units as the primary system of measurement in the UK” was published in 1995 – not 1985.

    You might have mentioned UKMA’s report “Metric signs ahead” in 2006, together with our estimate of £80 million (in contrast to the DfT’s £700 million).

    I wonder how strong the evidence is that failure to metricate properly has led to the demise of British industry. The case of British Leyland supports the theory, but then it always was a basket case and probably beyond saving from the early 1960s onwards. Perhaps incompetent metrication (by which I mean, for example, relying on conversions from imperial, and trying to run both systems rather than thinking metric) was a symptom of a wider inability of insular British management to adapt to a more competitive global economy.


  2. The year 2013 shows the hypocrisy of the government in relation to the use of units of measure.
    The government recently released a set of documents. The first which was presented to Parliament giving an overview and justification for Phase II of the High Speed Line was entirely in imperial units. This document can be found at

    The second release was two sets of documents showing engineering drawings of the route. They were entirely in metric units and can be found at:

    It would appear that the document presented to Parliament is in breach of both UK and EU law – the use of miles for administrative purposes only being permitted for use road signs, distances and speeds, not for those associated with new railway lines. One would have thought that after the West Coast Mainline franchise debacle, the Department for Transport would have taken care to observe every full stop and every comma of the law.


  3. @Erithacus says:
    ….. However, we should not fool ourselves that there is an inevitable progression toward full metrication. The history since 2000…..

    Very true. DfT will be the real stumbling block for many years, one way or another it affects just about everyone in the country, resident and visitor alike. Pints of milk and even pints in the pub are of relatively minor importance. Those issues will persist until the appropriate government action is taken, with little scope of influencing it.

    One issue I think should and could be pushed though is the NHS.
    To my mind there is little point in the law requiring written records to be metric if that is reversed at the point of first human contact. I was routinely weighed recently and instantly asked if I wanted that, quote, “In English units” by the nurse. Just what is the point of the law? Quite clearly medical staff at best consider it a joke, and possibly even object to having to use metric at all, the reality escapes them. We all know about babies “still being weighed in pounds” being nonsense but is really believed to a point where even I begin to wonder.
    In my view the NHS should also ban conversion tables within the department, and take active steps to stop staff using this practice of converting. If a patient does not know their weight or height in metric then they should be asked to convert it themselves, or be re-weighed and measured in metric, NOT converted by medical staff, it is not their job. Are medical staff trained in mathematical manipulation of patient weight and height?


  4. The question that arises from this history is how metrication could be encouraged in the UK. Obviously, the attitude of the Department for Transport is a major stumbling block to metrication. However, a lot could be done despite this.

    *Northern Ireland is an obvious area where movement on the roads is more possible. There is considerable minority support for a change to metric road signs in the Northern Ireland Assembly, so it could be worthwhile to urge the Assembly to take action to metricate their road signs.

    *The Channel Islands and the Isle of Man might be prepared to take a lead in metricating their road signs. The idea of being first to move in this direction could appeal to islanders, if only for the interest and publicity that it could generate. This could be appealing to the Channel Islands because of their proximity to the France, and to the Isle of Man’s proud identity.

    *In other areas, progress could be made by finding areas where usage is mixed. For example, local councils often describe the areas of their parks in hectares or square metres. The councils which still use acres to describe their parks and gardens might respond to a simple appeal to switch to hectares, especially when they are told that the Royal Parks in London are described in metric measures.

    *A similar issue arises with sporting codes. Some football and rugby teams use metric measures for describing their players, while others use both metric and imperial units and a few still use just imperial units. (The overall bodies and the BBC just use metric measures.) Simply writing to the relevant clubs could persuade at least some to switch to using both units. Those who provide both measures should be alerted to any inconsistencies between the measurements. This might persuade them that using just the metric measures for the heights and weights of players could be simpler and easier for them than juggling two sets of measures.

    These steps are not at all glamorous, but over time they could result in significant movement towards the wider usage of metric measures.


  5. I am not wholly convinced that banning conversion table within NHS departments is the correct policy, I see a case to provided them for patient’s use only. NHS staff would be forbidden to use them except to say “Here is the chart if you wish to convert to imperial units yourself”.


  6. “2008 … The UK Government then claim credit for ‘saving the pint and the mile’.”
    This pronouncement was clearly intended for a UK audience, but what message would it have sent to our overseas customers:
    * The UK is living in the past.
    * We are unwilling to change.
    * We are not part of the global economy.
    * You, our overseas customers, need to fit in with our requirements.
    * We are not really ‘open for business’.
    Just the opposite of the messages that the PM has been promoting on his recent overseas trips.


  7. It would be ideal if Wilfred’s comment is passed on to a much wider audience, including all Members of the House of Commons and the House of Lords who do not support the immediate completion of metrication in the UK.


  8. Now, at the beginning of 2015 it is obvious that thinking in the Department for Transport has moved. Height and weight signs will be switched so that all are metric/imperial. These, apparently, are to be introduced as the old signs wear out,

    Another area where the Department might be willing to move might be on the motorways between Dover and London and Southampton and London. Perhaps they might be open to considering dual kilometre and mile distance signs on these routes.


  9. @ Michael Glass

    I would avoid dual signage in kilometres and miles – people would merely ignore the kilometres and continue the miles. Though perhaps, when we do eventually metricate road signs – supposing we followed the Irish model of metricating distance signs over a period of years before speed limits are done in one day – we could metricate these routes commonly used by non-UK residents that you suggest (plus maybe the M25) in one swoop at the start of the project to “showcase” metric measures and get more people used to them quicker!

    Though, I’m sure the DfT would rather metricate a small country road near Little Kimble first, then say it’s made no difference and call the whole thing off before it’s even begun.


  10. I think the idea here is to break the blockade constituted by the absolute prohibition of metric units on road signs.

    Yes, it would be better to adopt the approach the Irish followed. Nonetheless, if the resistance to metric-only signage is too strong at the moment, better to slip the nose of the camel under the tent first with dual Imperial-metric signs. 😉


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