Elaine Prince-Patron, from Watford, Hertfordshire, has spent more than a year in a maximum security jail near Phoenix, Arizona, alongside murderers, after being found guilty of possessing marijuana for sale.
Mrs Prince-Patron, 54, is not eligible for parole until 2017, because an Arizona state court committed her to life imprisonment with a minimum of 25 years. 'This is hell,' she told the Independent, speaking by telephone from jail.
Her sentence, passed in February last year, was mandatory as she was already on probation for a 'serious drug offence' - again involving marijuana - when she was convicted.
The marijuana was discovered when detectives, acting on a tip- off, arrived at her home in Tucson. Although they did not have a warrant, she let them in. They found 81lbs (37kg) of the drug in a laundry room that her son was using as a bedroom.
The day after the raid, her son, Anthony, 31, was arrested in a nearby hotel after being caught with 60lbs (27kg) of marijuana. He was later sentenced to 18 months in prison in Texas, after appearing before a more lenient federal court.
Several weeks before the discovery of the drugs at her home, Mrs Prince-Patron had been placed on four years' probation after being caught at Tucson airport, where she was about to board a flight to New York, with 18lbs (8kg) of marijuana. She admitted that crime, but said she was delivering the drugs on behalf of her son, following threats by a dealer.
She adamantly denies having anything to do with the drugs in her son's bedroom.
The local prosecutor's office admits that the police found little other evidence to suggest she was a dealer: there were no large sums of money in her home or bank account, and no weapons.
She is planning to appeal, but cannot afford a private lawyer to fight the case.
Mrs Prince-Patron said her other son, James, 37, a decorator who lives in Watford, had taken up her case in Britain.