A lawyer says motorists caught breaking variable speed limits on some stretches of motorway may be able to get their conviction overturned. Prosecutors believed the signs did not comply with traffic regulations - and had the status of advisory rather than mandatory signs. Motoring solicitor Marcus Johnstone said drivers stood a 'favourable' chance of getting their cases reviewed in the Magistrates Court. The variable speed signs were introduced since 2006 - and have resulted in thousands of convictions.