Specially protected British foods like Stilton cheese and Melton Mowbray pork pies face significant difficulties after Brexit when European Union nations will be free to produce their own copycat versions, according to the Liberal Democrat’s Brexit spokesperson Nick Clegg.

“Outside the EU they won’t enjoy the appellation bestowed on those products and I would have thought other countries would take advantage of that pretty quickly and put products into the European market that directly rival those protected brands,” Mr Clegg told a food and drink industry conference.

The absence of any sort of deal on foodstuffs given specially protected status by the EU would also allow British manufacturers to produce their own versions of parma ham and edam cheese, a state of affairs all parties are likely to want to avoid. It would also, in theory, allow pasty makers from other parts of the UK to produce and sell Cornish pasties.

The UK has 73 protected foodstuffs, including Jersey royal potatoes.

He said the idea of a ‘low-cost bonanza’ discussed by many Brexiteers was ludicrous.