A Vietnamese man tried to convince police he was Portuguese when they caught him with dozens of plants for a cannabis farm.
Long-Hieu Le pulled out the European driving licence in an attempt to hide his identity and remove suspicion.
But he looked nothing like the picture on the photo card and officers searched his vehicle.
The 32-year-old illegal immigrant, who a judge was told is keen to go back home, will be deported after his jail term.
Colin Meeke, prosecuting, told Swindon Crown Court how Le was pulled over in a BMW on the edge of town at 2.30pm on Friday, November 29.
Officers found a white plastic bag, from which came a strong smell of cannabis.
Another bag was inside it with two boxes containing a number of cannabis plants, about 50 per box. A further bag contained 10 individual square plant pots.
Mr Meeke said: “The defendant produced to police as his driving licence a Portuguese driving licence which clearly was not his. He is not Portuguese.”
He said it was difficult to assess the value of what was in the car but they were probably worth about £3,000 in their state.
It is thought the illicit plants were due for two cannabis farms in houses on Welcombe Avenue in the Parks and in east Reading.
Le, of no fixed abode, admitted possessing class B drugs with intent to supply and possessing an identity document with improper intent.
Martin Wiggins, defending, said Le was delivering the items as he had been instructed by someone higher up the chain.
He said: “Immediately prior to doing so he was given an identity document. It is not a face that looks like him at all. He didn’t know what to do with it when he was stopped by the police.
“It was a stupid thing to do bearing in mind it bears no resemblance to him. He is thoroughly contrite and deeply ashamed of what he has done.
“It has been his dream for many years to return to Vietnam and he has not had the means. He is going to be returned, it is the only benefit to him out of the entire affair.”
Jailing him for a year Judge Douglas Field said: “You played a minor role as a courier but bearing in mind the background I put this case in the high bracket in the sentencing guidelines. “You also pleaded guilty to possessing a forged driving licence and this again has to be dealt with in the context of you being an illegal immigrant.”
A 38-year-old woman, Vang Hoang, of no fixed abode, was freed last month after she denied a drugs charge and the case against her was dropped.