A ‘sophisticated’ Vietnamese drugs gang grew cannabis on an ‘industrial scale’ as part of a million pound plot.

Members of the ten-strong group were jailed for 37 years in total after the criminal enterprise was discovered in a sting operation.

A total of 2,500 plants with a street value of £1,000,000 were recovered after officers raided 18 properties in north west UK.

Some of the cannabis farmers had been working to repay debts to people who had smuggled them into the UK, Preston Crown Court heard.

The investigation was first prompted after an abandoned Toyota car led police to a property in Blackburn that harboured 110 plants.

The discovery sparked a wide scale inquiry that looked into cannabis growing in homes, including in Bolton, Bury, Atherton, Leigh and Merseyside.

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

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.

Ringleaders Thanh Nguyen, 20, Dung Pham, 28, and Tung Pham, 26, were jailed for between 54 months and six years at a previous hearing.

Tung’s partner Nga Pham was also jailed for 54 months.

Quy Nguyen, 57, and Tan Vo, 55, were jailed for two years apiece earlier this year.

Speaking after the hearing, Det Sgt Stu Peall of Lancashire Police, 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.’