Lord Justice Laws has backed the case of five small British traders as they appealed against a government ruling that they exclusively use the metric system when selling fruit, vegetables, fish and meat.

The traders, dubbed the Metric Martyrs, were given convictions by magistrates in Sunderland, Cornwall and London for their continuing to sell goods in pounds rather than kilograms.

The Conservative government issued regulations between 1990 and 1995 to comply with two European Union directives, and thereby made it a criminal offence to use imperial measures. Previously, the Weights and Measures Act 1985 specifically enabled the continued use of the imperial system alongside metric.

Lord Justice Laws told a packed courtroom however that it was "shameful" how such a massive change could have been imposed without an Act of Parliament. By joining the EU, the British government had "voluntarily surrendered the once seemingly immortal concept of the sovereignty of Parliament", he added, maintaining that: "If I had had this case in a lower court, I would have halted it for an excessive abuse of process."

Remarkably, the judge's comments were made in anticipation of a judgement on the case, which is due in the next few weeks.