POLICE have arrested two men following a raid at a suspected cannabis factory at a Hampshire industrial unit.

Officers discovered what is believed to be “large quantities” of cannabis after raiding a two-storey warehouse at the Millstream Industrial Estate in Christchurch Road, Ringwood, at around 10am yesterday.

Officers discovered what is believed to be hundreds of plants inside.

The police helicopter was drafted in to assist and police confirmed all suspects have been detained.

A spokesman from Hampshire police said: “We conducted a drugs warrant and have made two arrests. A 25-year-old man and a 26-year-old man were arrested at the scene.

“A cannabis factory appears to have been located.

“Large numbers of plants were discovered over two storeys of the building.”

John Haskell, a valeter who was working on the estate when the raid took place, said one of the suspects escaped on to the roof after police smashed their way through the front door of the empty warehouse.

“The man just appeared on the roof,” he said. “It looked as if he was going to jump on to one of the vans below at one point but he didn’t.

“There were police officers all around the building.

“He seemed to be hiding for quite a while. Then the police appeared through a little trap door on the roof.”

Kevin Akester, a warehouse assistant at Chillers for Hire, which is opposite to where the raid took place, said: “One minute it was all quiet and calm and then I opened the door to bring the forklift out and there were police officers everywhere.”

Mr Akester said he and his co-workers were shocked by the news.

“I have been here since July last year and we always thought the unit was empty,” he said.

This is the second raid to take place at the Millstream Industrial Estate in the past three years.

In September 2011 officers raided a food production unit at the estate and discovered more than 1,000 cannabis plants.