Undercover police have swooped on an illegal brothel in Norbury, finding three girls, a madam, drugs and weapons.

Eight officers forced their way in to the flat about 2pm today, making three arrests and seizing an unknown quantity of cocaine and two CS spray canisters.

Inside they found five rooms containing pornographic material, flat-screen televisions, lubricants and tissues as well as an office for booking clients and taking their cash.

Three Spanish-speaking girls were found in the flat along with a woman believed to be the premise's madam and a male bouncer.

One girl was found smoking a cigarette alongside a semi-naked client in an upstairs room.

A man and a woman have been arrested on suspicion of managing a brothel.

Two women were also arrested on suspicion of violating Section 33a of the 1956 Sex Offenders Act.

Officers stormed the building after receiving information the property was being used as a sex den and following the return of a "test purchaser" sent in today.

Detective Sergeant Simon Stevenson said: "This operation was designed to ascertain whether or not trafficked women were being forced to work there against there will."

One female sex worker was allowed to leave the building and soon after her partner turned up with documents showing her British work status.

A middle aged man, believed to be the bouncer of the property, was arrested following background checks into his immigration status and for assisting in the management of a brothel.

The raid is the latest in a series on brothels across south London that has led to 14 arrests so far.

In one incident a female sex worker was found hiding in a wheelie bin after jumping out of a window to escape detection.

A nearby restaurant owner who wished to remain unnamed said: "I had no idea anything was going on up there."

A dozen CCTV cameras covered the flat's entrance, hall and various rooms in the building.

Each room was equipped with panic alarms.

An officer who asked not to be identified said: "A customer in one of the rooms had his shirt off, when he saw us he got a bit of a shock.

"The punter' was rather sheepish as he left the building, making a swift exit from the scene."

During the course of the raid a woman turned up claiming to be an agent for the owner of the property.

She said she came to the building twice a month to make sure it was all in order.