BUSINESS owners working in units close to where police uncovered a professional cannabis factory have spoken of their shock at the discovery.Officers swooped on the illicit factory, housed in a former MOT testing station on the Threxton Road Industrial Estate in Watton, late on December 20 after a police patrol spotted buckets of cannabis in the back seat of a car they had stopped.

BUSINESS owners working in units close to where police uncovered a professional cannabis factory have spoken of their shock at the discovery.

Officers swooped on the illicit factory, housed in a former MOT testing station on the Threxton Road Industrial Estate in Watton, late on December 20 after a police patrol spotted buckets of cannabis in the back seat of a car they had stopped.

The discovery has been hailed as a key victory in the battle against the production of drugs in the county and those working in business units close to the clandestine factory have revealed just how difficult is the challenge faced by the police looking to crack Norfolk's drugs rings.

Despite working day in, day out, within metres of the crime scene, all said they had no idea a major drugs operation was being run right under their noses.

Debbie Tennent, who works as a PA at nearby EIAT electrical installation, said: “Nobody suspected.

“We had not seen anything suspicious and we are always going out there to our cars and things. There was noting at all, no cars, nothing.”

The former MOT testing station is at the back of the industrial estate and is hidden from the main access road.

The business is understood to have closed about two years ago.

Richard Brooks, from Sue's Canoes, said his company had investigated relocating to the larger premises less than 12 months ago.

He said: “We never heard or saw anything. It has been boarded up for ages and this has just shocked everybody.”

The discovery is the latest in a series of drugs factories uncovered in homes and industrial units across Norfolk including Norwich, Lyng, near Dereham, Yarmouth, King's Lynn, Terrington St Clement, Thetford and Attleborough.

When police raided the Watton factory they found 591 cannabis plants being grown under a complex heat and lighting system.

Extensive work had also been done inside the former garage to insulate it and make it secure.

Police suspect a second room in the building was also being set up to grow cannabis plants and it is believed that those involved were growing their crop on a 13-week cycle with the operation worth about £100,000 each harvest.

The 65 lights used in the operation all operated on 600 watt bulbs on a 12 hour on, 12 hour off system.

The electricity meter had been bypassed to avoid detection.

Three men are in police custody in connection with the discovery.