Sept. 14 (Bloomberg) -- London government officials may introduce a ban or tax on plastic shopping bags in a bid to improve the environment.

London Councils, which represents the U.K. capital's 32 boroughs, began a monthlong review of the issue and will use its findings to help draft legislation, the group said in a statement on its Web site today. In July, the councils proposed a 10-pence-a-bag (20-cent) tax.

The group says it's facing a landfill problem because Londoners annually use 1.6 billion bags, which take 400 years to decompose. The British Plastics Association opposes bans or taxes, saying bags create an insignificant amount of waste. Ireland added a tax on bags in 2002, while San Francisco banned them at large supermarkets this year.

``People need to realize that the `free' shopping bag they pick up in the supermarket is not really free at all -- certainly not in its cost to the environment,'' Sean Brennan, the London Councils executive for sustainability, said in the statement.

The group is seeking comments from the public through Oct. 26 on options such as a tax, an outright ban or taking no action. It will consider the comments before compiling a package of proposals on London legislation that will go to Parliament.

The plastics association, the industry's main lobbying group, said in a statement on its Web site that plastic bags ``aren't a significant component'' of litter, making up less than 1 percent of garbage. Cigarette butts cause a bigger litter problem, the association said.

To contact the reporter on this story: Brian Lysaght in London at blysaght@bloomberg.net.

Last Updated: September 14, 2007 09:20 EDT