VIETNAMESE crime bosses are making at least £2million a year from drugs factories in East Lancashire, it has emerged.

And now detectives are lauching a top-level crackdown in a bid to smash the illegal industry.

Police said Burnley and Nelson had become hotspot areas for Manchester-based gangs due to the amount of empty homes.

The scale of the problem means Lancashire police’s Serious and Organised Crime Unit has prioritised the problem and the county’s officers are liaising with counterparts from neighbouring forces, such as Greater Manchester and West Yorkshire.

At Burnley Crown Court yesterday two Vietnamese men pleaded guilty to cultivating the drug after officers discovered a huge cannabis farm with a potential street value of £80,000 after swooping on the Duke of York pub, in Colne Road, Burnley.

Hai Nguyen, 23, and 34-years-old Ha Nguyen, both of no fixed address will be sentenced later this month for the production of cannabis.

Meanwhile, Tuan Pham, 46, of no fixed address, has admitted the same offence after police arrested him at a different property in Colne Road where a cannabis farm was found.

Last month police found drugs worth £150,000 in a raid of a cannabis factory in Nelson and in June a £1million cannabis growing project was also uncovered in the town.

Det Insp Dean Holden said: “This is clearly big issue because we have got Vietnamese organised crime groups setting up these farms.

“We are determined to crack down on this crime and we will leave no stone unturned in our efforts to root out those who are responsible and put them before the courts.

“Our message to offenders is clear — it is simply a matter of time before you too will receive a visit from police.”

Mr Holden also revealed the way criminal ganglords exploit vulnerable Vietnamese immigrants to keep watch over huge drugs farms.

He said: “They use ‘patsies’ which are generally low-level parts of the group who are usually indebted to gangmasters for their transportation or smuggling into this country.

“We have had convictions in the past and we are always making inquiries into who is behind it all.

“What we find is that the Vietnamese are good at farming cannabis.”

The hierarchy sees poor Vietnamese immigrants shipped over to Britain by gangmasters who order them to work in factories or face deportation.

Above them are often co-ordinators - who organise equipment to grow the plants - and financiers - bosses who bring the drugs in.

Mr Holden added: “It is a massive money-making scheme but the people who do the donkey work get nothing.”

The huge set-ups have led the county’s police to take drastic action, including Operation Freight, which recently saw Burnley man Masood Akbar jailed for five years for running heroin and crack cocaine factories.

Meanwhile, Operation Fugo, which was begun earlier this year by police, has uncovered several drugs farms in the area.

“We are looking into organised crime groups, from robberies to people trafficking and drugs,” added Mr Holden.

“We are continuing meetings with key individuals to discuss this.

“We discuss who is the greatest threat and then we use warrants, for example.

“But some of the best results have come from people saying there’s something odd going on across the road and us looking into it.”

Research in the Drugscope’s Druglink magazine, showed that far from being a “window sill” hobby for enthusiasts, cannabis growing is becoming a big business dominated by Vietnamese criminal gangs.

The average factory produces around £70,000 worth of cannabis every 11 or 12 weeks — worth about £250,000 to £300,000 a year.

The report also identified a new breed of “guerrilla cannabis growers” who plant marijuana on other people’s land and return three months later to harvest it.

Increasingly, police are also using heat-detection devices — including helicopter sweeps — to pick up on the presence of the many lamps needed to grow hidden crops.

Tell-tale signs include covered windows, late visitors, lots of black bin liners, compost and gardening equipment.