Police made one of the largest seizures of hard drugs in recent times when they smashed down the door of an Oxford flat.

Eight officers raided the second floor flat in Bayswater Road, Barton, at 11am on Thursday and seized packages of what they believe to be crack cocaine and heroin worth thousands of pounds.

They then searched two other homes in Moorbank, Blackbird Leys, and Bicester Road, Kidlington where they found £4,000 cash and drugs paraphernalia.

Oxford police spokesman Tim Wiseman said the substances had to be weighed and tested but six blocks found were believed to be crack cocaine weighing 1.75oz. He said a separate bag of what was thought to be heroin weighed 0.25oz.

Det Sgt John Linsdell, of the Oxford robbery team, hailed it as a blow against the supply of drugs in the city.

He said: "This is the largest single seizure of suspected Class A drugs for some time in the city and I'm confident that it will disrupt the supply network and the associated crime."

Officers raided the Barton flat at 11am, arresting a 52-year-old woman on suspicion of possessing class A drugs with intent to supply.

As officers searched, a 36-year-old woman arrived at the flat and was also arrested. A third woman, 49, was then arrested in a car parked nearby.

A 26-year-old woman was later arrested on suspicion of conspiracy to supply Class A drugs. All four have been released on police bail.

Det Sgt Linsdell added: "This is another excellent result for Operation Backlash and I hope it will send a strong message out to the people of Barton that we are listening to their concerns about drug use and supply in the area.

"On searching the house we recovered a significant quantity of drugs which will be tested to confirm their composition and quantity.

"I continue to stress that where the community of Oxford work with police and pass on information on those involved in crime, particularly drugs, we will act."

Det Insp Mark Ponting, of head of Oxford's priority robbery, burglary and autocrime teams, said: "Backlash has been very successful so far. The officers are getting out on the streets and mixing with the criminal fraternity, showing them we are looking over their shoulders."

Anyone with information about drugs or drug-related crime in Oxford can contact police on 08458 505505 or Crimestoppers on 0800 555111.