Marks & Spencer is to stop giving away free plastic bags under its Plan A eco-initiative. From 6 May each food carrier bag will cost 5p, which will be donated to charity.

Trials of the scheme in more than 50 stores in Northern Ireland and the south west of England have led to carrier bag use falling 70%. "If M&S customers right across the UK cut the number of bags they used by 70%, they would save more than 280 million bags every year," said Sir Stuart Rose, chief executive.

In the month before the charge is imposed, customers will be given a free 'bag for life' when they buy food.