DETECTIVES in Blackburn unravelled a million-pound plot to grow cannabis "on an industrial scale" after raiding a non-descript terraced house.

An investigation, sparked by an abandoned Toyota car, led officers to a property in Wellfield Road, where 110 plants were discovered.

But Preston Crown Court heard this triggered a widescale inquiry, focusing on a "sophisticated" operation by Vietnamese nationals to grow cannabis in homes across the north-west.

Prosecutor Michael Goldwater said the headquarters was traced to an address in Stenhills Crescent, Runcorn.

But 18 houses in total, across Bolton, Bury, Atherton, Leigh, and several addresses on Merseyside, formed part of the drugs factory.

Mr Goldwater said more than 2,360 plants were recovered during the investigation, which if broken down into street deals would have netted £1million.

Four Vietnamese men - Quan Dang, 32, Hung Pham, 29, Tran Hung, 36, and Vo Duc, 20 - were jailed for between 31 and 48 months, for their roles supporting the network. A fifth defendant, Quang Ngo, 44, will be sentenced in December after a trial of issue.

Judge Robert Altham, sentencing the quartet, said: "This was the production of cannabis on an industrial scale, a sophisticated set-up which was well-capitalised."

Duc was found tending 122 plants at a house in Montserrat Road, Bolton, when police raided the house, and confessed he had been performing that role for two months.

The ringleaders, Thanh Nguyen, 20, Dung Pham, 28, and Tung Pham, 26, who arranged for complex lighting and heating systems to be installed at the properties, were jailed for between 54 months and six years at a previous hearing. Tung's partner Nga Pham was also jailed for 54 months.

Mr Goldwater said Dung Pham, who effectively ran a rest and relaxation hub for cannabis growers in Dawson Street, Bury, and a cannabis farm in Firs Lane, Leigh, was found to have bought "colossal" amounts of beef, lobster and other seafood.

|Investigating officers believed at one point he might have been running a catering business because of the size of his orders from Costco.

And Quy Nguyen, 57, and Tan Vo, 55, who after they were caught out in Blackburn moved their cannabis operation to The Sheddings, in Bolton, were jailed for two years apiece earlier this year.

Det Sgt Stu Peall, of Lancashire Police's human trafficking team, said: " This was a sophisticated organised criminal group making huge amounts of money from their operation."

"Lancashire Constabulary will continue to proactively target the production of cannabis which can have lasting physical and mental health effects on users as well as having a negative effect on our communities and fuelling other crime and we are determined to tackle that."

The court heard some of the cannabis farmers had been working to repay debts to people who had smuggled them into the UK.

Mark Stuart, for Hung Pham, said his client was brought into this country in a refrigerated lorry from Germany at one point.