An illegal immigrant sentenced for cultivating cannabis in Wembley was smuggled here to help raise money for his dad - who was injured in the Vietnam War.
It emerged in Harrow Crown Court that Trung Le travelled from Vietnam in a lorry because his dad could no longer work, after suffering a brain injury when he was shot in the conflict.
But when he arrived 24-year-old Le soon turned to producing the Class C drug after the hotel he worked at near Heathrow was busted for employing immigrants.
He had been earning less than minimum wage working as many as 16 hours a day, seven days a week, but when that fell through he turned to drug production.
Le had already served a five and a half month sentence for running a cannabis factory in Greenwich when police found more than 400 plants in his home in Mount Pleasant, Wembley, in November last year.
A police helicopter had spotted an unusual amount of heat coming from the house and a raid found hundreds of plants being grown throughout the house.
Le was found hiding in the attic.
On Friday he was ordered to 20 months in jail but was warned he may be deported before his sentence is over.
Judge Graham Arran showed some sympathy for what he described as a degree of exploitation but said this kind of problem was becoming all too familiar.
He said: "This is becoming a common phenomenon that we see more and more in this court, and as long as this kind of behaviour is tolerated the exploiters will carry on doing it.
"Ultimately however, he didn't have to come to this country and he has refused to learn his lesson.
"This man is very unlikely to be in this country for very long but I fear that when he returns to Vietnam this problem will still be the same."