People living around a cannabis farm were none the wiser it had been raided, they said today.

Eastern Daily Press: Some of the 250 cannabis plants seized from an address at Walsoken, near Wisbech Picture: Norfolk ConstabularySome of the 250 cannabis plants seized from an address at Walsoken, near Wisbech Picture: Norfolk Constabulary (Image: Archant)

Police seized 250 plants, with an estimated street value of £125,000 from an undisclosed address in Broadend Road, on the outskirts of Wisbech.

But those living or working along the ribbon of bungalows and businesses, cut in half by the busy A47, were oblivious to Tuesday's raid.

"We're here 24/7, seven days a week, and we didn't see any police or anything," said a worker at a food business on Broadend Road's western arm.

A woman in a nearby bungalow said she hadn't seen or heard anything either.

Eastern Daily Press: People living and working on Broadend Road West said they had heard or seen anything suspicious Picture: Chris BishopPeople living and working on Broadend Road West said they had heard or seen anything suspicious Picture: Chris Bishop (Image: Archant)

The story was the same the other side of the A47, where one man said: "If anything like that had happened I'd know about it, believe me."

A neighbour added: "The first thing I knew was when it was on the news. They said the house was empty, but I don't think there's anywhere empty down here." The days are brief and cold in the Fens, as the shortest day approaches. Yet the crop found by King's Lynn police was happily flowering.

Nurtured by powerful lights in reflective draught-excluding tents, tucked away in a couple of rooms, it was draped in the buds which produce sinsemilla - the most powerful dope and most lucrative return, whether sold as weed (dried leaves) or resin.

Officers have said little about their find, other than no-one was in when they came calling armed with a warrant. Unlike many crimes, cannabis growing can be a hands-off operation, with automated watering or even hydroponic systems which bathe roots in a soup of nutrients taking care of the plants' every need until they mature, meaning growers rarely need to visit the scene of the crime.

Eastern Daily Press: Some of the 250 cannabis plants seized from an address at Walsoken, near Wisbech Picture: Norfolk ConstabularySome of the 250 cannabis plants seized from an address at Walsoken, near Wisbech Picture: Norfolk Constabulary (Image: Archant)

Insurer Direct Line Business said police seize an average of 900 cannabis plants a day.

It says tell-tale signs landlords should watch for include smell, the noise of whirring fans, cabling outside the property being used to illegally extract electricity and blacked-out windows.

Fellow insurer Cia Landlord said there was a trend for cannabis to be grown in small scale operations in residential properties.

Eastern Daily Press: Broadend Road East, close to the A47 Wisbech bypass Picture: Chris BishopBroadend Road East, close to the A47 Wisbech bypass Picture: Chris Bishop (Image: Archant)