Mr Thoburn and Mr Herron have a �100,000 fighting fund

Announcing his appeal plans on Friday, Mr Thoburn said he had decided to carry on his fight because of the level of international support he had received.

"People have asked me to pursue this further not for any political party whatsoever, just the people in the street, so obviously I want to take it further," said the Sunderland trader.

Public donations have swollen an appeal fund to �100,000 but it is thought an appeal in the Divisional Court in London could cost up to �500,000.

History's 'most famous' bananas

Mr Thoburn's case has won attention across Europe and was supported by the UK Independence Party (UKIP).

Mr Thoburn and his fellow trader Neil Herron, a fishmonger who has also been ordered to change his scales, were both dubbed "metric martyrs".

Europe's 1994 Units of Measurements Regulations came into effect on 1 January last year, amending the 1985 UK Act.

Trading standards officers seized Mr Thoburn's scales from his market stall in Southwick, Sunderland, on 4 July 2000, following the introduction of the directive.

In sentencing Mr Thoburn, District Judge Bruce Morgan said: ""An officer bought a bunch of bananas for 34p that were priced at 25p per pound and weighed out on a weighing machine and sparked a court case around, possibly, the most famous bunch of bananas in legal history."

Mr Thoburn now uses dual-measure scales.