Metrication refers to converting to the Metric system of units. The metric system was developed in France in 1795, with all measurements based on decimal divisions. The term metric comes from metre the French unit of linear measure. This system is now officially called Système international d’unités, the International System of Units, or SI for short.
In the United Kingdom metrication has been carried out half-heartedly since 1969, leaving a confusing mix of measures. Whilst officially the UK operates a metric system, long distance is still referred to in miles. In addition in common discussion many will continue to use Imperial terminology.
Despite this it became illegal in 2000 to sell loose goods in Imperial measurements. However the mixed use continues here. This is because as long as it doesn’t stand out more than the metric measurement, you are allowed to include imperial measurements on your packaging. Furthermore whilst milk is officially measured in litres it continues to be sold in pint-sized containers. In addition Imperial measurements are still used when ordering draught beer or cider, or in returnable milk bottles. The Troy Ounce continues to be used for precious metals as well.