The Plaid politician said she was “amazed” at how little Welsh meat there was on sale at a supermarket in the town.

“I found no end of New Zealand lamb and poultry products from Holland and Poland,” she said.

Speaking at the National Assembly in Cardiff, she accused some supermarket chains of not giving Welsh produce sufficient prominence, leaving shoppers to search stores to buy Welsh.

This week the Church of England added its voice to Britain’s food debate by insisting an independent ombudsman should be “urgently considered”.

In a report submitted to the Competition Commission, it said the pursuit of cheap food, coupled with the buying power of the big supermarkets, was putting farming livelihoods at risk.

The Church is an investor in the food retail sector and its Ethical Investment Advisory Group is concerned at the business practices of the big multiples.