A man lunged at police with a carving knife as they raided a suspected drugs den in the Sussex force's biggest ever crackdown on dealers.

Officers blasted the man with pepper spray in a dramatic raid on a house in Montpellier Road, Brighton.

The swoop last night was part of Operation Disrupt. This morning police swamped Brighton railway station in a bid to trap the "cocaine commuters" who are believed to be ferrying drugs to the city from London.

Plain-clothes officers and dog handlers mingled with passengers as they stepped off trains. Spot-checks were carried out on the A23.

Meanwhile, uniformed police carried out high-profile patrols in known drugs hotspots.

The operation aimed to flush out dealers in the run-up to Christmas.

Detective Chief Inspector Andy Buchan said: "We want to cut the supply of drugs into Brighton and Hove, to disrupt the routing and to disrupt the local market.

"We are sending out a message that the supply of drugs into our area will not be tolerated."

The operation began at 6pm yesterday when three flats were raided simultaneously by a team of 20 officers.

PC Darin Birmingham led the raid on the flat in Montpellier Road.

He said: "As we came in a guy came at us and pulled out a carving knife so we sprayed him."

Two other men in the bedsit were also showered with pepper spray, forced to the ground and strip-searched.

Flats in Portland Road and Buckingham Street were also raided.

A total of 12 men, aged between 21 and 36, have been arrested so far. None are believed to live in Sussex.

They are being questioned in connection with suspected drug dealing offences, affray, obstructing police and handling stolen goods.

Police suspect one of the men was carrying 22 rocks of crack cocaine.

Cannabis with a street value of £1,000 was found, as well as cash and stolen cheques.