Two-system muddle – now sorted?

If you are frustrated when navigating your way through Britain’s muddle of two measurement systems, then help is at hand. But first we outline how the country got itself into this mess.

The Royal Commission of 1819 followed the principle laid down in Magna Carta, six centuries earlier, namely, “Let there be one measure …”. The timeline on the UKMA web site provides more information:

1819. A Royal Commission is appointed to consider more uniform weights and measures. In their first report, the Commissioners agree that a uniformity of weights and measures is obviously desirable, but link decimalisation of measures to decimalisation of the currency. It recommends simplifying English customary measures rather than using the metric system.

1824. The proposals of the Commission are the basis of the Weights and Measures Act 1824 and of the Imperial system that follows from it. This Act establishes standards for the primary units and ‘tidies up’ arcane laws without radically changing the multiplicity of customary weights and measures used throughout the country. Indeed, it expressly states that “it shall [be] lawful [to] buy and sell goods and merchandize (sic) by any weights or measures established either by local custom or founded on special Agreement” provided their exact relation to the standard units defined by the Act was generally known.

It was almost 40 years later when the first step down the slippery slope of two systems was taken:

1862. A Select Committee of Parliament publishes a report unanimously recommending that the use of the metric system should be made legal but that “no compulsory measures should be resorted to until they are sanctioned by the general conviction of the public.”

1864. The Weights and Measures (Metric System) Act permits the use of metric measures for ‘contracts and dealings’.

Advances in the use of the metric system in the UK, for example in science, and its adoption by many countries around the world persuaded Parliament thirty years later to take a another step down the slippery slope:

1895. A Select Committee of the House of Commons recommends that the metric system should be authorised for all purposes, taught in elementary schools and become compulsory within two years.

1897. A second Weights and Measures (Metric System) Act permits the use of the metric system for all purposes in the UK. Like the 1864 Act, this Act has little practical effect.

The advance of the metric system continued during the 20th century, both in the UK and around the world. Realising that there was a risk of the country’s industries losing export markets and becoming less competitive, Harold Wilson’s government announced in 1965 that they “… consider it desirable that British industries on a broadening front should adopt metric units sector by sector, until that system can become in time the primary system of weights and measures for the country as a whole …” and that “the Government hope that within ten years the greater part of the country’s industry will have affected the change.” The programme would be voluntary and costs would be borne where they fell. And, in an echo of the Report of the Royal Commission of 1819, Wilson’s government gave the go-ahead for decimal currency to replace £sd.

The metric system did indeed become the UK’s primary measurement system, and £sd also passed into history. However, some of the measures defined by the Act of 1824 would continue in use for some purposes. This was highlighted recently by the report of the TIGRR, which endorsed a particular aspect of the two-system muddle and is the subject of an earlier article on Metric Views.

Today the choice, which was seen in 1819 to be between English customary measures or the metric system, has become that between the existing mix of two systems or the use of a single, coherent system of measures for the country as a whole.

And what about those who have difficulty picking their way through this mess? Two charts have recently been published which may assist.

The first appeared on reddit:

A simpler version has been created by Andrew Lohman:

So, sorted? Or perhaps not.

The timeline may be found here:

4 thoughts on “Two-system muddle – now sorted?”

  1. Weights and measures were considered in the Acts of Union between England and Scotland in 1707 which contains this provision:

    XVII. ‘That, from and after the Union, the same Weights and Measures shall be used throughout the united Kingdom, as are now established in England; and Standards of Weights and Measures shall be kept by those Burghs in Scotland, to whom the keeping the
    Standards of Weights and Measures, now in use there, does of special Right belong. All which Standards shall be sent down to such respective Burghs, from the Standards kept in the Exchequer at Westminster, subject nevertheless to such Regulations as the Parliament of Great-Britain shall think fit.

    So this might be the first attempt in legislation at standardisation?


  2. It would be amusing if it were not true. Pretty much as I try to explain the UK system to others.
    I do seriously wonder what UK government and MP’s would make of this in a ‘debate’ in parliament about our units of measure. My guess they would all have a good laugh, then pass it as the de-facto system.
    Why change a working model?


  3. Given that it seems even older persons do not know the difference between UK and USA measures, and the creep of the latter into our ‘system’, I would suggest we now have a three system muddle.
    Three systems must surely be much better than just one or two.


  4. It’s a bit pathetic, isn’t it! However I’d like to look at one item – milk.
    One-Stop local convenience shops sell cartons of milk by the litre. It is also notable that they sold weighed-out produce in metric in the early 1990s – several years before this became compulsory.
    One-Stop is a sub-brand of Tesco. Could it be that Tesco uses One-Stop for pilot studies – response to change causes less of a reaction in the smaller local shops, which are not usually subject to local competition? Could this be a prelude to a more-widespread sale of milk in litre containers?


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