Thang Nguyen (48), thought to be a Vietnamese national, charged with producing cannabis, appeared before Mansfield magistrates on Friday.

Four other Nottinghamshire men, aged between 25 and 28, a 34-year-old Hucknall man and a 20-year-old foreign national have been bailed.

Officers seized 3,000 plants in the raid on Barrows Hill Lane.

Seven men in total were arrested on suspicion of cultivating cannabis during the raid at the former chicken factory, on Barrowhills Lane, on Wednesday.

Hydroponics and other drug making paraphernalia, including £250,000 worth of electrical equipment, were disconnected and seized.

Said Chief Insp Mark Wakeland: "One attending officer, who has executed drugs warrants for the past seven years, said it was the biggest and most sophisticated set up he had ever seen.

"Cannabis plants were being grown on an industrial scale across the factory floor - a huge space roughly 50m long by 25m wide.

"An immensely professional operation was running on site, to the extent that upstairs office space had been converted into living quarters complete with a gymnasium.

"We have confiscated approximately 3,000 cannabis plants - an incredible result thanks to information passed on by community .

The raid was sparked by an anonymous tip-off to Crimestoppers.