POLICE have raided a cannabis factory which could have produced more than £200,000 worth of the drug every year.

Officers from Bromley police's CID task force used a search warrant at a semi-detached house in Anerley Park, Penge, at 12.30pm on April 30.

One upstairs room was already set up to grow cannabis and contained 311 cannabis plants along with the mother plants, from which cuttings had been taken.

Police estimate the room could have produced cannabis worth £46,650 every 12 weeks.

Four of the rooms were in the process of being set up to produce cannabis and contained equipment such as plastic sheeting, ventilation systems, lighting systems and fans worth more than £14,000.

Detective Sergeant Gary Gornell, who led the raid, said: "The successes we have had recently in disrupting what are very sophisticated cannabis production set-ups are due in no small part to members of the public who have contacted us with their suspicions.

"These cannabis factories are elaborate operations and are not something which can be set up and run in a residential street without them coming to the attention of people living and working in the area."

Det Sgt Gornell said there are many ways to spot a cannabis factory and people should look for the warning signs.

He said: "Most cannabis factories will emit a strong and unusual smell. Neighbours may hear a lot of banging noises as the factory is set up and see people coming and going with bags of fertiliser and compost and other equipment such as powerful lights.

"It is also likely the curtains will be kept closed at all times but bright lights may appear to be left on around the clock.

"Residents living in the street are again likely to see various comings and goings when the crop is harvested, such as bags being loaded into a vehicle."

He added: "I am also particularly appealing to landlords to be aware of what to look for.

"If the tenant always pays in cash and does not allow access to the property, let us check it out."

No arrests have been made in connection with the raid on the house but police are working with the landlord of the property to identify and trace the tenants.

Anyone with information should call Bromley CID on 020 8284 8895.