The man behind a huge cannabis factory worth £2.8 million, with more than 6,000 plants growing inside, has been jailed.

Pham Tuan, 28, was today sentenced to four-and-a-half years’ imprisonment, over the enormous factory discovered in West Hill, Dartford, back in August 2013.

Once released he will be deported back to Vietnam.

Tuan pleaded guilty to being concerned in the production of a class B drug and to other charges brought by Merseyside Police in connection with a second factory in Liverpool.

Kent Police officers made the initial discovery, with plants at various stages of growth inside the derelict Dartford building, St Lawrence House.

Experts estimated that the cannabis had a potential street value of £2.8 million but that this figure could be up to three times higher with previous crops taken into account.

Extensive ventilation systems had been fitted throughout the property and there was also evidence of illegal electricity abstraction.

Officers also discovered a notebook containing reference to watering and compost, which was forensically linked to Tuan.

In November 2015 Merseyside Police notified investigators from the Kent and Essex Serious Crime Directorate that Tuan had been arrested.

Senior investigating officer DS Richard Spicer said: "Pham Tuan was a key player in a major drug supply operation, and stripping down a cannabis factory of that size would have undoubtedly made a big impact on the county’s drug network.

"Tuan may have felt like he had got away with it but his arrest should serve as a warning to others that no unsolved case is ever truly closed, and that if you break the law your crimes will catch up with you in the end.

"We have a zero tolerance approach to drugs and I am pleased Tuan will never again be able to grow cannabis plants within the UK."