Sir, David Cameron showed how out of touch he is when he said he would “still go for pounds and ounces” (Oct 1). Adopting the metric system was discussed in parliament as early as 1818. Attempts at metrication by science and industry followed, but political weakness scuppered the system being rolled out nationally. Nonetheless, half a century ago Britain and France jointly built a fully metricated supersonic passenger jet: Concorde.

In 1965, the then Federation of British Industries informed the government that its members favoured adopting the metric system. Today every major industry in Britain is metricated. The Conservatives are obviously not in the 21st century.

John Redman

Heathfield, E Sussex

Sir, Further to Janice Turner’s remarks on metrication (Notebook, Oct 2), I