A fourth man has been arrested following the seizure of cocaine with an estimated street value of £50m in Rochester.

The 33-year-old was arrested yesterday at an address in north London on suspicion of conspiracy to supply class A drugs and money laundering.

Metropolitan Police officers also seized half a million pounds in cash.

It follows an operation in Rochester on Monday, during which the huge quanity of cocaine was discovered and three men were arrested.

Officers from the Metropolitan Police had been carrying out an investigation into an organised crime network involving the supply of class A drugs.

They say the seizure has disruputed a "significant supply of cocaine into London".

DI Colin Stephenson said: "We'll continue to combat the criminal networks engaged in drug trafficking and prevent a large amount of cocaine flooding the streets this Christmas."