Unilever's new mustard mill in Norwich is likely to be enough to allow it to continue marketing its famous mustard as Colman's of Norwich, according to a food law expert.

The producer is closing its factory of 160 years at Carrow Works, and will set up a new facility at an as-yet-unconfirmed location where it will employ 25 people to mill and pack mustard powder.

Dr Andy Bowles, a specialist food law solicitor at ABC Food Law in Norwich, said Unilever would only fall foul of legislation if consumers were seen to be misled about the food's origins.

'If they were moving lock, stock and barrel to Burton-upon-Trent, and the Norwich connection was something that attracted consumers to the product, that would be misleading,' he said.

'If they are milling it here, they would probably argue they are doing enough – they just aren't putting it in the pots in Norfolk.'

Dr Bowles said manufacturers could apply for different kinds of protection for their brands, based on either geography – such as Melton Mowbray pork pies, which must come from within a certain distance of the Leicestershire town – or based on process, such as mozzarella, which must be produced in a certain way to be recognised as such.

He drew a parallel between the Colman's question and a legal case over Sheffield steel, when manufacturers moved part of the process to China.

'The courts ruled that they were doing a substantial part of the process in Sheffield, and they were doing enough to keep the name,' said Dr Bowles.