The Hartlepool Mail reported Tuesday that Thanmanh Nguyen, 18, fled from a house on St Paul’s Road in Hartlepool town when police carried out a raid last July.
Officers found more than 260 cannabis plants, an iPhone and £40 ($51) in cash inside, a Teesside Crown Court heard.
"[The plants were] spread over two floors and four rooms," prosecutor Chris Wood said.
While Nguyen admitted to having produced "a class B drug" on July 26, 2018, he claimed he had been trafficked from Vietnam two years ago and forced to water the plants.
Nguyen’s defending lawyer, Andrew Turton, said the cannabis farm was already in operation when Nguyen got there and somebody else was in charge of it.
"[Nguyen] watched as that person was beaten for apparently refusing to carry on looking after the plants.
"[Nguyen] never left the house because he was fearful of the consequences of doing so."
Nguyen was sentenced by Judge Stephen Ashurst, who said it was a large and sophisticated cannabis grow and there was nothing to support Nguyen’s claim he was coerced into looking after the plants.
The plants and growing equipment were ordered to be confiscated and destroyed.
Nguyen will be deported after serving his sentence.
Last month 16 Vietnamese nationals had been jailed in the U.K. for between eight months and 7.35 years for running illegal cannabis farms worth $1.2 million in Lancashire.
Britain was home to at least 136,000 modern slaves, according to last year’s Global Slavery Index by rights group Walk Free Foundation, a figure 10 times higher than a government estimate in 2013.
Experts say children are being trafficked from Vietnam and other countries to work in illegal cannabis farms, and that the scale of the problem has been vastly underestimated, Reuters reported.
Jakub Sobik, a spokesman for Anti-Slavery International, said, "Potentially thousands of children and young people are being trafficked from Vietnam and exploited by ruthless criminal gangs."