Police have warned that people who buy alcohol for drunks in Truro could face prosecution as part of fresh efforts to control drinking in the city centre.

An initiative by police to control the problem by advising retailers against selling to people who are drunk has been a partial success in curbing "troublemakers and drunks", but officers say that CCTV evidence suggests alcohol is now being bought by the public on their behalf.

Neighbourhood beat manager for the city centre PC Dave Harris said that buying drink for people under false pretences was actually an offence and they could face prosecution.

He said: "During the day these persons get more and more drunk. They sprawl out on the benches on Lemon Quay or the bus station, they urinate in public places or leave empty bottles and cans all over the place and then they start fighting each other.

"By buying alcohol for these persons you are causing problems for the law-abiding people within the city centre," he said.

Mr Harris said that not only was this kind of anti-social behaviour frightening to members of the public, but it was also a drain on police resources in dealing with numerous calls they receive about drunks every day.

"We should be proud of Truro. Having drunks hanging around the streets does nothing for the image of the city. Don't think you are doing a favour for someone buying alcohol on their behalf - you are in fact the cause of a lot of problems involving these people," he said.

There is a hard core of 15 to 20 street drinkers who repeatedly cause problems, according to Mr Harris, but he said Truro got a new wave of "vagrants" in the run-up to Easter each year and police fear the problems could escalate.

"At the moment it is not a massive problem but if we don't put our foot down now it could get worse," he said.

Dave Burleigh, owner of the Lemon Quay Spar shop located near popular street drinking spots, said: "We stop it whenever we can, but it is very difficult to know who people are buying the alcohol for."

Mr Burleigh said that the shop no longer served known drunks and actually banned people whom they suspect of buying alcohol for others. "I sometimes follow people out of the shop to see if they are buying for the drunks, but we can't catch everybody. We don't want to stop selling alcohol for genuine people, but we would be delighted if they would only buy for themselves," he said.

He added that the problem had "massively improved" since community policing started in the area. "Three years ago this place was like a riot every night - now we hardly ever have to call the police," he said.

The manager of the Co-op store in Boscawen Street, Charles Mellow, agreed that the situation had improved since the summer, but said that occasionally they did have to turn people away. "We used to only stop selling to people who were drunk, but now we refuse anyone who we think are likely to be drinking in the street.

"If someone comes in with a nice suit but orders a bottle of cheap sherry then we often refuse," he said.

Police say they are mounting an ongoing operation throughout the year in conjunction with shop owners and the public.