A Vietnamese illegal immigrant who helped to manage a network of sophisticated cannabis factories in Bradford has been jailed for four years.

Leeds Crown Court yesterday heard that Sen Trinh, 31, became involved in the Drugs trade when his application for asylum was turned down in 2006 and he was unable to work.

Prosecutor David McGonigal said Trinh, who pleaded guilty to conspiracy to produce cannabis, was involved in eight properties in Bradford and Manchester where tens of thousands of cannabis plants were cultivated. Two houses in Horton Grange Road, Bradford, had been converted into cannabis factories, adjoined by a tunnel at the top. More than 16,000 skunk cannabis plants with a street value of £150,000 were found.

Skunk cannabis plants with an estimated street value of between £200,000 and £300,000 were found at a second property in Dirkhill Road, Great Horton.

Trinh, of Manchester, was arrested in February 2007 and bailed but failed to attend when required. The landlord of the Dirkhill Road property contacted police after recognising him when drugs squad officers appealed in the Telegraph & Argus for information about people who had gone on the run.

Trinh finally handed himself in to police in Bradford last July after a further appeal on the BBC’s Crimewatch programme.

Judge Jennifer Kershaw QC said Trinh had been directly involved in the day-to-day running of the Bradford factories.

She said he was not a “gardener” and a manager’s assistant was an accurate description of his role.

She said: “When you are not engaged in these activities you are a good family man, well thought of. But this offending is so serious only custody is appropriate.”

Khadim-al-Hassan, mitigating, said the defendant had come to the UK in 2003 after being persecuted in his native country. He was threatened when he realised those employing him were cultivating cannabis and was worried that he would be reported to the authorities.

Trinh is now awaiting the outcome of an appeal to the Home Office against the rejection of his bid for asylum.

After the case, Detective Inspector Neil Benstead, of Bradford District Drugs Team, said: “Trinh was a significant player in an organised crime group. Work continues in this special area of large-scale cannabis production and we are clearly identifying new suspects through DNA work. The profits remain huge, with money being pumped back into crime networks. Sentences such as this have a huge disruptive effect.”