A policeman has been questioned by detectives after cocaine worth nearly half a million pounds was seized in a drugs raid.

The officer has been suspended from duty after three kilograms of the class A drug were found during an operation in Brighton.

Force insiders say it is one of the biggest hauls of the drug to be found in the city.

Police are so far unable to confirm the purity of the cocaine seized but a single kilogram of pure cocaine can sell for £150,000 when cut and sold in small batches on the street.

The officer was arrested on suspicion of money-laundering and possession of cocaine with intent to supply as part of an operation by Sussex Police’s major crime unit.

He was questioned and released on bail while the investigation continues.

Three other men have been arrested by officers from Sussex Police’s serious organised crime unit as part of the same operation.

Darren Simpson, 41, of Coney Furlong, Peacehaven, was charged by police with possession of cocaine with intent to supply after he was stopped by police on the A272 last Wednesday.

He appeared at Lewes Magistrates’ Court on Saturday and was remanded in custody. He is due to appear by videolink at Brighton Magistrates’ Court today before being brought back for a committal hearing in May.

The other men were arrested and questioned before being released on bail while officers carry out further inquiries.

Experts giving evidence in previous trials for drug plots in Sussex have estimated the street value of a gram of cocaine at £50.

Dealers cut the drug one part cocaine to two parts mixing agent, meaning three kilograms of pure cocaine would be worth about £450,000 if diluted and sold to users.

Sussex Police declined to comment on whether they were concerned any of the force’s work had been compromised as a result of the operation.

A spokeswoman for Sussex Police said: “We can confirm a serving Sussex police officer has been arrested in Brighton as part of an ongoing criminal investigation.

“He has been interviewed and bailed without charge pending further inquiries. He is currently suspended from duty.

“It would be remiss of us to comment further as criminal proceedings in this case have commenced.”