Contrary to popular belief, the adoption of the metric system as the primary system of weights and measures in the UK is not a recent trend. Nor is it particularly to do with the European Union. Indeed, as the timeline below demonstrates, the quest for a single, rational system of measurement goes back to Magna Carta.
| 1215 | Magna Carta requires “one measure” of wine, corn and cloth throughout the realm; and similarly for weights. |
| 1668 | Bishop John Wilkins, in England, publishes a proposal for a universal decimal system of measurement. |
| 1670 | Gabriel Mouton, in France, proposes a decimal measurement system. |
| 1707 | Treaty of Union extends English standard weights and measures to Scotland |
| 1790 | French National Assembly sends delegates to Britain, Spain and the United States to propose cooperation in units of measurement. Cooperation is rejected by Britain. |
| 1795 | Republic of France adopts French Academy of Sciences recommendation for a decimal Metric System. |
| 1799 | The platinum standards for metre and kilogram defined for decimal Metric System |
| 1824 | Weights and Measures Act phases out many traditional units and establishes the standard imperial system. |
| 1861 | A committee of the British Association for Advancement of Science (BAAS) including William Thomson (later Lord Kelvin), James Clerk Maxwell and James Prescott Joule introduced the concept of a coherent system of units which is fundamental to the modern metric system. They proposed the metre, gram and second as base units. |
| 1862 | Commons Select Committee unanimously recommends adoption of metric units for public administration. |
| 1864 | Weights and Measures Act legalises metric units only for ‘contracts and dealings’. |
| 1873 | A BAAS committee proposes centimetre, gram, second (CGS) base units using prefixes from micro to mega. They also propose a unit of electrical resistance (later named the ohm). |
| 1875 | Metre Convention established by diplomatic treaty to co-ordinate world metrology. International Bureau of Weights and Measures (BIPM) established. |
| 1881 | The first International Electrical Congress adopts various BAAS recommendations on electrical units (in the metric system). |
| 1895 |
Commons Select Committee recommends:
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| 1896 | Weights and Measures (Metric System) Act legalises metric system for all purposes, but does not make it compulsory |
| 1904 | House of Lords votes for compulsory change to metric system, but Bill fails in House of Commons. |
| 1914 | The UK Met Office follows the lead of the International Meteorological Organisation (forerunner of the World Meteorological Organisation) and adopts the millimetre as the official standard unit of rainfall measurement. |
| 1939 | Davidson Committee proposes unified and metrically-based National Grid as common framework for Ordnance Survey mapping. Adopted 1940. |
| 1951 | Board of Trade committee recommends ‘organised change’ to metric system. Report seen as premature and not implemented. |
| 1959 | British and US inches (which were different) standardised as exactly 2.54 cm. |
| 1963 | Weights and Measures Act redefined the basic measures of the ‘yard’ and the ‘pound’ in terms of the ‘metre’ and the ‘kilogram’. Many of the old imperial measures were abolished (drachm, scruple, minim, chaldron, quarter, rod, pole, perch, and a few more). Imperial units are now defined in terms of metric. |
| 1965 | At the request of industry, President of Board of Trade announces that the metric system will be adopted with a target of completion within 10 years (i.e. 1975). Commonwealth and other countries decide to follow Britain’s example. |
| 1968 | Metrication Board established. However Board restricted to providing information and not permitted to promote benefits of the metric system. |
| 1970 | Re-surveying of UK begins to include metric elevations in Ordnance Survey maps. |
| 1971 | British currency decimalised. The much-feared changeover proved to be well organised and smooth. Massive Government information campaign to prepare the public for change. |
| 1972 | White Paper on Metrication advocates gradual not compulsory change. |
| 1973 | UK enters EEC and reaffirms commitment to adopt metric system. |
| 1974 | Metric system required to be taught in British schools. Metric packaging begins. |
| 1979 | New Government abolishes Metrication Board. |
| 1980 | Most Commonwealth countries have completed metric conversion. Britain lags behind significantly. |
| 1988 | British scientist Dr Terry Quinn appointed as Director of International Bureau of Weights and Measures (BIPM) |
| 1989 | EEC agrees UK request to secure delay in implementation of some aspects of the metric system |
| 1995 | UK regulations require packaged goods sold in Britain to be labelled in metric units. Negligible information provided to public. |
| 2000 | UK Regulations require goods sold from bulk to be measured and priced at the point of sale using metric units. Negligible information provided by Government to help public use metric units. |
| 2004 | Prof Andrew Wallard, former Chief Metrologist of UK’s National Physical Laboratory becomes Director of BIPM |
| 2009 | EU amends Directive to permit “supplementary indications” alongside metric units. Also withdraws requirement for UK to “fix a date” to convert road signs to metric units. Acre is phased out for land registration. |
UK Metric Association 