With Tesco and Asda ­having long since carved up the UK fashion market through their wardrobes of stylish yet affordable sweat-pants and wifebeater short-sleeved shirts, it was surely only a matter of time before the world of haute couture hit back.

Dame Vivienne Westwood, the doyenne of British fashion who's still more punk in her seventies than a vat of Country Life made with John Lydon's spit, has waded into grocery. She's backing Cool Earth Coffee, a new eco-brew that channels 20p per purchase towards planting trees in the Amazonian rainforest. Apparently, each jar sold protects a tree which in turn can lock in a tonne of carbon dioxide.

"Cool Earth Coffee is one of the most powerful environmental products people can put in their supermarket trolleys," said director Matthew Owen, presumably not referring to the caffeine content.

Look out for future ­connections between clothing and coffee, with Debenhams reportedly plotting a new line called 'Mocha, John Mocha' and Starbucks pressing on with its long-time quest to have 95% of the British workforce wearing its famous uniform by 2013.