Retailers have stood up to Farmers For Action picketing the depots; tolerated farmers standing outside their stores with anti-corporation leaflets; and have even been forced into checking produce for name and shame stickers.

Now they may have to face up to the formidable might of the Women's Institute.

This week a petition of nearly 72,000 names was handed into the House of Commons, calling for a watchdog to oversee the milk industry and to strike a better deal for farmers.

A similar number of postcards have been sent to Downing Street, along with 6p in change per card to represent the difference between what farmers got 10 years ago for their milk and what they get now.

Describing it as one of the organisation's most successful petitions and campaigns ever, Stephanie Fort, one of the campaign's leaders and herself a dairy farmer, said more activities were planned.

Between 23 April and 4 May, the WI would be joining forces with the NFU to launch The Great Milk debate in London, she told The Grocer. This would be "a period of intense awareness-raising activity, and will involve Federations and WI from across the UK holding local debates", Fort explained at a recent dairy conference.

She said the debate would help to bring farmers, milk processors and retailers together to debate the situation of the industry, and would discuss dairy with an audience made up largely of consumers who would help reach agreement on the ways forward.

Tom Hind, NFU chief dairy adviser, said it was vital to find out whether consumers really did care about the plight of dairy farmers and their animals if they were to win support from supermarkets.

"I'm not sure we've yet found the killer argument ­

to get the retailers to act," Hind added.