Has Asda gone bananas? Kickstarting a price war this week by slashing banana prices from 77p to 72p, it met with an immediate response from its big four rivals. And immediate condemnation from a number of suppliers and NGOs.

But its timing couldn't really be better. A little over a year ago, it was Sainsbury's that stole all the headlines, with its switch to Fairtrade.

But times are different, and this move is a big test of the currency of Fairtrade in a market where consumers are really feeling the squeeze.

As the UK's most popular fruit, the banana has always been a totemic item for supermarkets, and the price cut is sure to play well with consumers (as well as Alistair Darling).

The timing also coincides with a plentiful supply. And with Sainsbury's forced to follow suit, it could even hurt its direct rival, which is committed to Fairtrade.

Asda even appears to have considered the ethical repercussions, setting up new direct terms with suppliers that, it claims, are every bit as good as Fairtrade.