In 2001, market trader Steve Thoburn was convicted of what the authorities thought was a ‘crime’ worth punishing: using nonmetric scales to sell bananas.
He was one of a group of traders who became known as the Metric Martyrs for their ultimately unsuccessful campaign to choose what units of measurement are used by traders.
Ever since the process of metrification began in 1965, the ancient system of Imperial units – such as pounds and ounces for weight and yards and inches for length – has been largely sidelined by officialdom.
From 1985, all pre-packed goods were sold in metric measures of kilograms and grams. Then, in 2000, all goods sold loose by weight also had to be weighed using the metric system.
The Imperial system stretches back to the Middle Ages, when it evolved from the array of Roman, Celtic and Anglo-Saxon local units used around the country.
In 2001, market trader Steve Thoburn (centre) was convicted of what the authorities thought was a ‘crime’ worth punishing: using nonmetric scales to sell bananas. He was one of a group of traders who became known as the Metric Martyrs for their ultimately unsuccessful campaign to choose what units of measurement are used by traders
The first official attempt to establish uniformity came with the Winchester Standards, which were in effect from 1588 until 1825.
It specified that a yard was three feet in length, with each foot containing 12 inches and each inch equalling the length of three barleycorns.
Units of capacity and weight were also officially laid out.
By the 17th century, statute and common usage had established the acre, rod and furlong at the values which they remain today: an acre is 4,840 square yards; a rod is 16.5feet and a furlong is 660feet.
The Weights and Measures Act of 1824 and its 1878 update officially established the British Imperial System – which laid out precise definitions of selected existing units.
A single imperial gallon replaced the varying wine, ale and corn gallons that came before.
And the two new basic units were the imperial standard yard and the troy pound. The latter was later restricted weighing drugs, precious metals and jewels.
The Imperial system stretches back to the Middle Ages, when it evolved from the array of Roman, Celtic and Anglo-Saxon local units used around the country. Above: A woman buying meat from a butcher’s in Doncaster in 1965 – the year that metrification began
Then, a 1963 act of Parliament got rid of measures which had fallen out of general use, such as the rod and chaldron, which measured coal.
The standard yard was then redefined as being 0.9144metres and 0.45459237 kilograms respectively.
According to Encyclopaedia Britannica, the gallon ‘now equals the space occupied by 10 pounds of distilled water of density 0.998859 gram per millilitre weighed in air of density 0.001217 gram per millilitre against weights of density 8.136 grams per millilitre.’
In other words, a British gallon is equal to 277.4 cubic inches (4.54litres).
However, when the US adopted its own official units, it chose those which had been discarded in the 1824 act. It means that the U.S. gallon 231 cubic inches – 17 per cent smaller than the British one.
As for a US bushel, it is derived from the Winchester version and so is around 3 per cent smaller than the British equivalent.
The British stone of 14 pounds is not used at all in the US. As for the ton – in the UK it amounts to 2,240 pounds, whilst its American counterpart comes in at 2,000 pounds.
The pressure for metrification began in the 1795, when the French devised a new system which featured the metre and the kilogram.
The idea was first formally discussed in the UK by a Royal Commission in 1818 and then in Parliament in 1824.
The issue was intertwined with the decimalisation of currency, which did not ultimately come into force until 1971.
In 1863, a bill which would have imposed the metric system throughout the British Empire nearly made its way through Parliament but was ultimately rejected for being impractical.
In 1896, the Weights and Measures Act (Metric System) legalised the use of metric units but did not make them compulsory.
It wasn’t until 1965 that the Government then began the metrification programme.
However, despite the fact that the process has continued at pace since then, millions of older Britons still continue to feel more familiar with Imperial units.
And, whilst younger Britons are now far more familiar with metric units, imperial measures have retained their power both on the roads and in pubs.
The pint is still used for draught beer, cider and bottled milk, whilst UK cars measure speed in miles per hour and road signs display distance in miles.
Whilst the European Union rigidly enforced the metrification system on member states, a concession allowed the use of imperial units as long as metric version were also displayed.
This did not help Mr Thoburn – passed away from a heart attack in 2004 – and other metric martyr traders, who were prosecuted for their insistence in using imperial weights and measurements alone.
Metric equivalents of the most common imperial weights and measures
Pound (16 ounces) = 0.454 kilograms
Ounce (16 drams) = 28.350 grams
Stone (14 pounds) = 6.35 kilograms
Mile (5,280 feet) = 1,609 metres / 1.609 kilometres
Furlong (660 feet) = 201 metres
Yard (three feet) = 0.9144 metres
Foot (12 inches) = 30.48 centimetres
Inch (0.083 feet) = 2.54 centimetres
Square mile (640acres) = 2.590 square kilometres
Acre = (4,840 square yards) = 4,047 square metres
Square inch = 6.452 square centimetres)