<P> The White Paper was published in February 1972, and it set out the case for metrication and refuted the charge of metrication by stealth as metric units had been lawful for most purposes since 1897 . It also reported that metrication would be necessary for the UK to join the European Common Market and that as British industry was exporting to all parts of the world they would benefit . It also reiterated the previous government's policy that metrication should be voluntary and hoped metrication would be mostly complete within ten years . The expectation was also expressed that with both the imperial and metric systems coexisting for many years, that consumers would gradually become familiar and comfortable with the metric system . </P> <P> Shortly after the publication of the White Paper, the Minister of Transport announced postponement of the metrication of speed limits, which had been scheduled for 1973 . The rest of the metrication programme continued, with the following completion dates: </P> <Ul> <Li> 1970 Electric Cable Makers Confederation, British Aerospace Companies Limited drawing and documentation, London Metal Exchange, flat glass </Li> <Li> 1971 Paper and board, National Coal Board designs, pharmaceuticals </Li> <Li> 1972 Paint industry, steel industry, building regulations </Li> <Li> 1974 Textile and wool transactions, leading clothing manufacturers adopt dual units </Li> <Li> 1975 Retail trade in fabrics and floor coverings, post office tariffs, medical practice </Li> <Li> 1976 Bulk sales of petroleum, agriculture and horticulture </Li> <Li> 1977 Livestock auctions </Li> <Li> 1978 Solid fuel retailing, cheese wholesaling, bread, London Commodity Market </Li> </Ul> <Li> 1970 Electric Cable Makers Confederation, British Aerospace Companies Limited drawing and documentation, London Metal Exchange, flat glass </Li>

When did uk start selling petrol in litres