Agents are being warned to be on their guard about the growing number of cannabis farms, as one former site in a London rental comes up for auction.

The two-bed flat in Finchley is being advertised on Rightmove, with much of its drug-making equipment still in place (see main picture).

The police warned of a proliferation of cannabis farms during the Covid lockdowns, leading law firm Hägen Wolf to issue a warning to landlords and letting agents – both of whom can be held criminally liable if they ignore suspicious activity.

“The landlord, and any helpful neighbours, should keep a detailed log of conduct such as night-time visitors, strange noises or any funny smells, which might indicate that illegal activity is taking place, and ideally supported by photographs and videos,” said Philip Copley, a solicitor with the firm.

“If it is safe and possible to report the matter to the council or police, then do so – that can create a paper trail which strengthens the landlord’s case.”

Incriminating signs of drugs

Signs of a cannabis factory include late-night comings and goings, a fan running constantly, windows with heavy condensation, a pungent smell or sudden fluctuations in electricity bills.

Production and possession with the intent to supply is a criminal offence that can carry up to 14 years in prison and an unlimited fine. Landlords and agents who are aware or have suspicions of a cannabis farm in one of their properties can be liable under law and face the same penalties.

The property in Ballards Lane, Finchley is being sold on 15 March by Auction House London with a guide price of £275,000. Its listing on the portal has been taken down.