Five market traders - so-called metric martyrs - are today taking their legal battle for the unfettered legal right to trade in pounds and ounces to the House of Lords.

They are asking the Law Lords, sitting in the highest court in the land, to give them permission to challenge a High Court ruling that European law "ranks supreme" in Britain.

Lord Justice Laws and Mr Justice Crane ruled in February that regulations made in line with EU metric policy were lawful, even though that meant "our Imperial measures, much loved of many, seem to face extinction".

The judges rejected the anti-metric campaigners' claim that European Union directives giving priority to the metric system's grams and kilos did not apply in England and Wales.

The case gained worldwide attention and marked the first head-on legal clash since the UK joined the European Community between laws made by Parliament and Euro law.

Backing for the anti-metric battle came from celebrities including singer Elaine Paige, actor Edward Fox, comedian John Cleese and Lord Tebbit.

Neil Herron, the Wearside-based spokesman for the Metric Martyr Defence Fund, warns that final defeat for the traders could signal "the death of democracy", but pledged that the fight, which has cost £100,000 so far, would continue to the House of Lords.

The campaigners argue argue that the 1985 Weights and Measures Act authorized traders to continue using Imperial measures, even though the UK had signed up to the 1972 European Communities Act and became subject to European directives.

The five "martyred" traders include greengrocer Steven Thoburn from Sunderland, who was fined for selling bananas by the pound.

Their counsel Michael Shrimpton described the five as "ordinary men without means or higher education but whose patriotism and courage puts ministers to shame".