Johnson said plastic bags were an "unnecessary scourge" on the environment and wants the city to be "bag free". He stressed the importance of cutting the number of bags in time for the 2012 Olympics, when "the eyes of the world are on us".
His comments come after a Waste and Resources Action Programme (WRAP) report revealed that the number of plastic bags handed out in the UK in 2010 had increased by 6% year on year. Recycling minister Lord Henley recently threatened to introduce plastic bag legislation and said retailers in England needed to "lift their game" to cut the number of bags handed out.
Johnson said he would be keeping an eye on Wales, which is introducing a 5p charge for single-use bags in October. In order to introduce a ban or charging scheme, London would have to apply for special dispensation under the provisions of the Climate Change Act 2008.