Cannabis plants discovered in a Shropshire warehouse would have earned the ringleaders £1.5 million a year, detectives revealed today.

A total of 1,850 cannabis plants, valued at £250,000, were discovered in the garden-centre style “cannabis factory” on Stafford Park in Telford during a raid on Monday.

Detective Constable Paul Stoddart-Crompton, of Telford’s drugs squad, who led the operation, today said the cannabis plants had been seized from the unit and put into 60 sacks. They have all since been incinerated.

See also: Inside county drug factory

Mr Stoddart-Crompton said: “We have seized 1,850 plants along with 238 sodium lights, all of which had its own electrical power pack. The estimated value for the crop we have seized is £250,000, but that has got a yearly earning potential of £1.5 million.”

Forensic teams have spent two days scouring the premises for clues as to who was behind the class-C drug growing operation.

“We have sent numerous items for forensic examination including toothbrushes and razors,” he said.

“As they were spooked they left everything behind, even to the point where one of them left in such a hurry he had one trainer on and one was still in the factory. We have got everything for DNA testing.”

Two men thought to be of Chinese origin were seen fleeing the scene when the drugs squad officers raided.

But Mr Stoddart-Crompton said even if the people behind the “cannabis factory” were in the country illegally he was hopeful of catching them. He said they will start another factory somewhere else and, “when they are arrested we will have their DNA on profile and it will be realised they were behind the Telford one too.”