Jake the labrador has become the scourge of city druggies as he patrols the streets to sniff out narcotics on passers-by.

His handler, PC Colin Richardson, said: "Jake can detect whether someone has been in contact with drugs up to of 24 hours earlier.

"He'll either sit down or just freeze by the person."

And his reward for a successful sniff?

PC Richardson said: "He gets to play with his tennis ball and have his tummy tickled."

Jake gets it right 87 per cent of the time and has been so successful he was recently asked to help patrol tube stations in London.

Jake has become familiar to some pushers and users, who cross the streets when they see him coming. But the telltale manoeuvre alerts police, who move in on the suspect.

Jake has joined Operation Frosty, a high-profile operation to clear druggies, beggars, shoplifters and drinkers from the St James's Street and London Road areas of Brighton.

Three people were arrested yesterday, including two for having offensive weapons, and a further seven people were stopped on suspicion of possession of drugs.

Inspector Beryl Bacon said: "We are determined the public enjoys Christmas shopping without being pestered by antisocial behaviour."

Extra patrols have been introduced to focus on known drug-dealing spots, including alleyways and the seafront.

Users were spotted yesterday waiting for a supplier in the children's playground on The Level.

Sergeant Bill Whitehead said legislation under the Criminal Justice and Police Act 2001 meant anyone drinking in the open can be arrested and their drink can be poured down the drain.

Cyclists abusing one-way systems and traffic lights were also targeted.

During a briefing to patrol officers yesterday, Sergeant Steve French said: "Beggars often congregate around cash point machines.

"We will not tolerate this and I want them moved."

Officers were joined by Councillor Mo Marsh, chairwoman of the Brighton and Hove City Council police consultation and public safety partnership.

She said: "We are fully supporting this high-profile operation by the police and I hope the public will feel more reassured while they go about their Christmas shopping."