A couple from Edgware have been jailed for seven years for their part in a £2.5 million drugs empire.

Ngoc Dao, 25, and her husband Jean Ephigene, 28, were part of a six-member gang that grew cannabis at a number of addresses across the UK.

They both admitted conspiracy to launder money and obtaining a money transfer by deception, at Norwich Crown Court on Thursday.

Ephigene also admitted conspiracy to produce cannabis, conspiracy to launder money and two offences of obtaining money transfers by deception.

He was sentenced to 54 months and Dao was given 32 months.

Joining them behind bars will be Dao’s mother and father Bich Nga Le, 42, and Hoang Hoi Dao, 53, both from Camberwell, and Luan Phan, 42, and his partner Phyuony Thi Nguyen, 33, both from West Lynn, Norfolk.

The gang received a total sentence of 26 years for one of the biggest drugs operations ever uncovered by Norfolk Police.

The gang members grew cannabis at two addresses in Norwich, another in Norfolk, one in Sunbury-on-Thames and one in London.

Police started their investigation in July 2006 after being alerted by a member of the public to suspicious activity at a house called The Lodge, in Crossbanks Road, King’s Lynn.

They raided the detached property and found it had been converted into a cannabis factory with a watering and lighting system built to help cultivate the drug.

More than 300 newly-planted cannabis plants and 500 mature plants were seized.

The court heard the factories produced between 75 and 100 kilos of cannabis a year, earning the group around £400,000 a year over a period of five or six years.

Detective Chief Inspector Colin Pearce said: “This is the largest money laundering investigation ever undertaken by Norfolk Constabulary.

“The sheer scale of this investigation required dedication by officers to bring it to a successful conclusion.

“Those officers and staff are to be commended for their efforts in this case.”

Phan was sentenced to four-and-a-half years; Nguyen was sentenced to two-and-a-half years and Le was sentenced to four years and eight months.

Hoang Hoi Dao received a seven-and-a-half year term.