A pioneering scheme to tackle underage drinking has been launched.

Sergeant David Conyers, from Cray Valley West Safer Neighbourhood Team, designed plastic bags allowing police to trace the source of illegally consumed alcohol.

He came up with the idea after seeing bags discarded by youths who had been drinking in the Cray Valley West ward.

They have been distributed to eight off-licences in the ward, each with a different colour and shops' names and addresses printed on.

Sgt Conyers said: "During the last four months the Cray Valley West Safer Neighbourhood team have seized an appallingly high number of alcoholic drinks from children.

"Youths seen in possession of the carrier bags suspected of containing alcohol will be searched and we will also be able to trace the bags found discarded at drinking spots back to the premises where the drinks were sold.

"We often find the remains of a late-night drinking event and could not identify from the dumped bags and containers what off-licenses were responsible."

The scheme is aimed at youngsters and adults buying alcohol for underage drinkers - an offence punishable with a fine of up to £5,000.

Bromley police are the first force in the country to introduce such a scheme, and have had enquiries from other Metropolitan Police forces about it.

Bags were distributed to shops over the weekend (April 5-6), and the scheme is under way.

It will take around two months to see how the scheme, funded by the Safer Bromley Partnership, is working.

It may then be introduced throughout the borough.

The off-licenses involved, all in the Cotmandene Crescent area, are The Local, A & A Stores, Costcutter, Cards & Fings, NISA Supermarket, Londis, Kishan Superchoice, and Fine Food & Wine.

The off-licences have each received 1,000 of the biodegradable, compostable bags, and price guns and labels to help identify the source of drinks.

Inspector Andy Johnstone, from Bromley police, said: "We are working hard to tackle anti-social behaviour across the borough and supplying alcohol to youngsters is irresponsible and undermines this work.

"I would urge anyone who suspects that an adult is guilty of this to contact the police on 01689 891212."