THREE men from the Great Yarmouth area are in custody on suspicion of possessing cannabis with intent to supply after police discovered a huge cannabis factory in Watton.

THREE men from the Great Yarmouth area are in custody on suspicion of possessing cannabis with intent to supply after police discovered a huge cannabis factory in Watton.

The drug haul, estimated to be worth up to £400,000, was seized from a disused former MOT testing station.

Good old-fashioned policing was at the heart of uncovering the factory late on Saturday night as two officers patrolling the estate stopped a car which had been parked outside.

Three people from the Yarmouth area were inside the vehicle and officers found buckets full of cannabis in the back and a set of keys which fitted the lock to the unit.

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

Describing the discovery in Watton, Sgt Colin Barratt, of Dereham police, said: “This is a major operation and we are looking at big-scale production by people who are very well organised and professional. It is a major find for the area in terms of potential harm it could do and it is a major disruption for the drugs industry.”

He praised the officers who made the discovery.

“It was good pro-active policing.”

Inside the building - which appeared empty and is right in a quiet corner of the estate - the officers found 591 cannabis plants in one part of the building which had been growing under an intricate system of lighting.

Extensive work had been done inside the building to create insulation to help the plants grow and prevent anything being seen or heard from outside.

It appeared a second large room was being set up to grow hundreds more cannabis plants - and there was also evidence that it was possibly being used for storage of equipment for further factories.

It is believed the cannabis plants were growing on a 13-week cycle with each one potentially being worth £100,000.

The three men in custody are also suspected of cultivating cannabis.