The environment secretary, Hilary Benn, has thrown his weight behind calls for supermarkets to stop selling as British processed food containing foreign meat.

Benn added to calls for more clarity on the issue after celebrity chef Jamie Oliver highlighted apparent inconsistencies in supermarkets' labelling of meat earlier this week. Benn said retailers were undermining efforts by the Governments to convince shoppers to buy British.

"If you buy something that has on the package 'Wiltshire cured bacon', I think most people would assume the bacon came from Wiltshire, but under the current European rules that is not necessarily the case," Benn told The Independent.

"You may turn it over and discover that actually it came from Denmark. Or if you buy, for example, Cumberland sausage you might assume that that is where the pork came from, but then you discover it's not from there – it's from somewhere else. Consumers are not getting clear information."

He added: "We know a great deal about the origin of our car or the house we buy. I think we should have better information about where our food comes from."

Tesco bowed to pressure from The Grocer this week to alter the labelling of British products after a story in the magazine revealed inconsistencies between the information on the front of the pack, and the fineprint on the back, which appeared to suggest that a product described as 'Produce of Britain' might also be from a number of other countries.

In a letter to The Grocer, to be published in this Saturday's issue, Tesco has promised to move to a simpler and clearer system of labelling on its products.

"We will change the front of pack wording to 'Produced using pork from Britain' and on the reverse it will state simply, 'Packed in UK'," it said in the letter.

"We hope this move will make things clearer for customers and demonstrate our continuing support for British farmers."