London moved a step closer to becoming the UK's first city to implement a ban on the distribution of free throw away carrier bags, including paper and plastic bags, after council leaders voted to include the proposals in a bill to be put before Parliament later this month.

London Councils chairman Councillor Merrick Cockell urged Londoners to lobby their MP to support the bill, which would impose a ban on the estimated 1.6bn free plastic bags distributed to London shoppers each year.

"The campaign to rid the capital of the environmental blight of throw-away shopping bags begins here," Cockell said. "As a society, we need to do far more to reduce the amount of waste we are sending to landfill and London as a city is determined to take an ambitious lead on this issue."

The vote follows an online survey of over 1,700 people that found that 90 per cent supported some action to reduce the number of plastic bags used, with 60 per cent calling for an outright ban.

However, it remains unclear whether MPs will support the plans.

The government has in place a voluntary agreement with retailers to cut the environmental impact of plastic bags by 25 per cent by 2008 and pledged in its Waste Strategy earlier this year to work to phase out free single-use carrier bags. But there have been indications that the Treasury would oppose any attempt to impose a levy on plastic bags and it is unclear if it would soften its stance for an outright ban.

David Tyson, chief executive of the UK Packaging and Industrial Films Association (PIFA), said there was evidence to suggest that any ban on free plastic carrier bags would lead to an increased environmental impact.

"Any ban would be a serious error of judgement," Tyson said. "When Ireland imposed a tax on plastic bags there was a reduction in the number of bags d istributed, but what happened is that people just went out and bought alternative plastic bags that were thicker. Customs and excise figures show that since the levy was implemented, the total weight of all types of plastic bags being imported to Ireland has increased."

"Thin plastic carrier bags are one of the most re-used forms of packaging around," said Tyson. "Some may ask why we are lobbying against this when it would lead to increased sales of plastic, but our view is that it is environmentally irresponsible."

However, a spokesman for the Irish Department for Environment, Heritage and Local Government dismissed the suggestion that the country's plastic bag tax was failing, insisting reports claiming sales of plastic bags and bin liners have undermined the environmental benefits of a reduction in the numbers of single-use bags were "anecdotal".

He added that government estimates showed the levy had resulted in a 90 per cent reduction in disposable bag use and that the levy had been increased earlier this year to ensure it remains effective.

The news comes as figures released by Sainsbury's suggest retailers' efforts to reduce use of disposable bags are having an effect. The company said that the use of free carrier bags fell by 10 per cent in the past six months, while the use of reusable bags rose by nearly 50 per cent, driven in some part by a series of promotions that have seen stores give out free reusable bags to shoppers.