Famous faces are putting their weight behind a campaign to save imperial measures.

Jilly Cooper, Jools Holland, Antony Worrall Thompson, and Sir Ranulph Fiennes are four of the 21 co-signatories who wrote an open letter to PM Tony Blair demanding a reversal of the Brussels directive that would make it illegal to mark goods in pounds and ounces alongside kilos and grams from 2010.

The letter condemned the directive as, "repression purely for its own sake."

Any mention of feet and inches, pounds and ounces, and pints and gallons, when describing goods for sale after December 31, 2009, will be illegal. Shopkeepers who ignore the change could be faced with fines of £2,000 and even jail.

The letter to Blair read: "It is no more than a malicious attack on our cultural heritage as well as our democracy. Not only do the vast majority of people not want a metric monopoly, a large proportion do not even understand metric units and, if that regulation is enforced, will be deprived of the necessary consumer protection afforded by a display of imperial equivalents."