In 1971 school cookery rooms in London receive instructions from Central Headquarters to get rid of all the equipment with old imperial measures and change everything to metric. The caretaker removes the sturdy metal jugs that measure pints and fluid ounces and we replace them with plastic jugs with metric millilitres.
Out with the old, heavy measuring scales with their iron weights for ounces and pounds and in with plastic scales measuring grams and kilos.
We’ve been through nationwide grumbles with the new decimal coins which gossip says it is a government trick to put up prices. Pennies and shillings are the new 1p and 5p coins and the ten bob note becomes a 50p coin. Shock! Outrage! I don’t want these pees! How will we add up the cost of things now? What is that price in old money!
But the world outside the classroom pays little attention to metric measures and carries on with the old measurements. The government makes little effort to enforce change. Milkmen deliver pints of milk in glass bottles, and pubs sell beer in pint and half pint glasses with a half pint of prawns to eat in the garden. Packs of lard and margarine come in 8 ounce packs and flour is sold in 3 pound bags. The greengrocer sells fruit and vegetables by the pound priced in shillings and pence and he may become a Metric martyr if he refuses to change. In the measuring world you still buy fabric and knicker elastic by the yard or in inches, and in timber yards wood is measured by the foot!
There’s no money for new recipe books so I translate the old system into the new, and the maths is complicated. There are 28 grams to the ounce, 454 grams to the pound, and one pint is 568 millilitres. Puzzled? So are we all. In my cookery classroom I must press forward into a metric future and my recipes must all modernise so no asking students to bring in a pound of cooking apples!
The history bit
Years later a student asked me ‘What does oz mean?’ I thought he meant Australia, but no, he was using a Delia Smith recipe who had maintained the old system and refused to change.
Timeline for decimalization and metrication
1971 British currency decimalised. A huge Government information campaign prepared the public for change.
1971 London schools adopt the metric system.
1973 UK enters EEC and commits to adopt the metric system
1974 Metric system taught in all British schools. Metric packaging begins.
1979 The new Conservative Government under Margaret Thatcher abolishes the Metrication Board.
1980 Most Commonwealth countries have completed metric conversion. But Britain lags behind.
1995 All packaged goods sold in Britain have to be labelled in metric units.
History of the metric system
The metric system started in France and was rapidly adopted in other European countries during the 19th century. In 1960 the Conference on Weights and Measures adopted the name International System of Units (Système International d’Unités or SI) for the recommended units of measurement. A hundred years after recognising the benefits of going metric, Britain announced it would adopt metric units in 1965.
Britain and the USA have yet to complete the changeover.
Imperial units, like metric ones, have roots abroad. Although the name “imperial” refers to the British codifying of units in 1824, many imperial units are based on Roman units used across Europe during the Roman Empire. Pounds and ounces have their roots in Italy and France. The abbreviation for ounce ‘oz’ comes from the Italian word onza.
Many of the students I was teaching from the 1970s would be approaching fifty years old so most of the population must have discovered metric measures by now!
Writing my book I taught them to cook in 2021 I found this website about milk being sold in pints.
itaughtthemtocook.com 
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