Two landlords discovered their exclusive four-bedroom property in Sutton had been turned into a cannabis factory after it went up in smoke.

Thirty firefighters were careful to avoid inhaling thick clouds billowing from the two-storey building in Lenham Road on Monday morning.

It later emerged that the electricity supply had been overloaded by high-intensity watering and lighting systems used to grow the illegal drugs.

Sutton police are believed to have recovered up to 500 cannabis plants from pots in a converted breakfast room and two reception areas.

One of the buy-to-let merchants, who wanted to remain anonymous, said: “When tenants are polite and seemingly doing what they are meant to do we like to respect their privacy.

"The lady who rented the house was from Hong Kong and seemed to be particularly polite and respectful.

“She paid the rent on time, never complained and when we passed the house it looked in pristine condition, with all the weeds removed from the block-paving.

“After hearing the news I felt sick and didn’t know what to do watching everything unfold.

"There must have been 500 cannabis plants inside and firefighters were shovelling out the peat.

“My husband has been a bit soul-destroyed and is now thinking of selling all the ‘let’ properties we have established over the past 14 years. The house was a total wreck.”

Detectives were following several leads having removed the plants and cultivation equipment on Tuesday afternoon.

A Sutton Police spokesman said: “When the fire brigade entered the premises they found the property was being used as a cannabis factory, with a large quantity of plants in three rooms inside.

“The address was rented to three tenants, who were not in at the time.

"The fire brigade remained on scene for most of the day, with the landlord and a large crowd.

"The Fire Investigation Unit has reported to police that the fire was started accidentally.”

A 300-plant cannabis farm typically produces about 50kg of “skunk” worth £150,000, at £3,000 a kilogram.

Officers have executed six warrants on drug dens in the borough since the start of the year.

Anyone with information about the fire or the tenants should call Detective Constable Charlie Lourenco on 020 8649 0747, or Crimestoppers, anonymously, on 0800 555 111.

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