"A 5p charge for plastic bags in England is to be introduced by the government in a bid to discourage their use.
Deputy Prime Minister Nick Clegg is to unveil the plans at the Liberal Democrat party conference this weekend.
The charge, which will only apply to supermarkets and larger stores, will begin after the 2015 election, with the proceeds going to charities."
There has been a decent amount of research looking at the effect of plastic bag taxes in Washington (article on same), San Francisco, Dehli, Wales and Ireland. Ireland's 15c tax on plastic bags in 2002 was a unqualified success, resulting in an estimated 90% reduction in bag use and a very positive public response. Wales has enjoyed similar success although the results in other areas have not been as dramatic.