The number of cannabis farms being found by police has trebled over the last two years, according to a report.
Charity DrugScope said 1,500 cannabis farms were found in London alone in the past two years, compared with around 500 in the previous two years.
Its magazine Druglink said over 60% of cannabis sold in the UK was grown here, compared with 11% 10 years ago.
The charity said analysis of police raids showed up to 75% of cannabis farms were run by Vietnamese gangs.
In the last 12 months, Vietnamese-run cannabis farms have been found in London, Birmingham, south Wales, the North East, Yorkshire and East Anglia, DrugScope added.
An average of 400 plants are recovered in a police raid, as officers continue to target farms in residential and commercial properties.
In London, where the class C drug is worth £100m a year, the Metropolitan Police says it has closed down two to three factories a day and destroyed 1.5 tonnes of cannabis a week over the past 18 months.
Most of the farms are in London but DrugScope said others have been raided as far afield as Glasgow, Birmingham, East Anglia, south Wales, the North East and Yorkshire
Charity spokesman Martin Barnes said many of the farms were set up in empty residential properties taken over by the growers.
"Sometimes, often because of the link with people trafficking, somebody can be committed to actually looking after the property," he told BBC News.
"We have come across cases where neighbours have actually reported the existence of these plants because burglars have broken into a house, have accidentally stumbled upon cannabis and have been seen running away with the stuff."