Nearly two years ago Mrs Prince-Patron, from Watford, Hertfordshire, was dispatched to a maximum security jail in the United States. Her crime did not involve murder or terrorism. She was not caught with a gun, or a bomb. In fact, she did not commit violence of any kind.
Yet she was sentenced to spend 25 years behind bars and razor wire. The earliest she will be eligible for parole is 2017, when she will be 79. She does not think she will live that long.
The offence which attracted this, the harshest penalty in America short of capital punishment, was far from uncommon, although few would seek to justify it. Drugs squad detectives found 80lbs of marijuana at her home in Tucson, Arizona, along with wrappers and traces on her clothing. She was found guilty of possessing the drug with intent to sell.
Worse, it was her second conviction, and came only weeks after she had been placed on four years' probation. Several months earlier she was caught at Tucson airport preparing to board a flight to New York with 18lbs of marijuana stuffed inside a suitcase.
But the extreme severity of her sentence has astonished lawyers. She has no other criminal record, beyond one petty offence (forging a pounds 20 cheque more than 30 years ago). David Bjorgaard, her lawyer, said: 'There is only one other single crime under Arizona law that could attract a sentence like this - and that's first degree murder.'
Mr Bjorgaard, who works for a top Tucson law firm, was so appalled by Mrs Prince-Patron's case that he recently agreed to represent her without charge. 'It is absolutely outrageous that she was sentenced to that amount of time. Any right-thinking person can see that,' he said.
His point is reinforced by sentencing patterns in the US. According to the US Sentencing Commission, drugs traffickers with a comparable criminal history to Elaine Prince-Patron's, but who are convicted in a federal rather than a state court, spend an average of five years in jail.
Sex offenders in the same category are locked away for just over seven years. And in the state system, first-time murderers are regularly released after less than eight years, while rapists are often freed before they have served four.
Elaine Prince-Patron was tried in Arizona, in a state court. She was therefore subject to the draconian laws passed by Arizona's legislature in an effort to abate drug-running into the US across its southern border with Mexico. Until recently, life without parole for 25 years was mandatory for anyone caught with dealing quantities of narcotics while on probation for a serious drugs offence.
She also had a chance to avoid life imprisonment. Before her trial, prosecutors offered Mrs Prince-Patron a plea bargain under which she would have received 5 to 15 years if she admitted guilt. She refused.
For, according to her, the marijuana did not belong to her but to her son, Tony. Why else, she argues, would she have let the police into her house? The authorities admit they had no search warrant.
Tony Prince, 31, a son by her first marriage to a Watford businessman, was arrested in a Tucson hotel with 60lbs of marijuana the day after his mother's home was raided. He pleaded guilty in a federal court and was jailed for 18 months. On his release, he was deported back to Britain.
According to Mr Bjorgaard, he has since signed a draft affidavit admitting the marijuana for which his mother was jailed for life belonged to him. (Mrs Prince-Patron also claims her son was linked with her first offence: she says she agreed to carry marijuana to New York only because he had a broken leg and was facing threats to his life from a drugs dealer.)
Whether her story is true or not - and she did not convince the jury - it helps her friends and family make sense of what has occurred. To them, she does not much resemble a dangerous criminal who deserves to be locked away for a quarter of a century.
Elaine Prince-Patron arrived in Arizona about 18 years ago and spent nearly a dozen years working as a waitress before becoming a self-employed seamstress. Anne Cardarella, a Briton who manages a mobile home park in Arizona, said: 'I used to go to her house two or three times a week, and I can tell you that she has a heart of gold.'
Mrs Prince-Patron now spends her days in Perryville prison, outside Phoenix, microfilming US government documents for 70 cents an hour, reading in her cramped double cell (which she shares with a murderer), or attending classes. She has already qualified in computer sciences.
Every fortnight her second husband, Robert Patron, a school cleaner, makes the four-hour round trip to the prison to visit her. He remains in a daze of disbelief. 'No one believes me when I tell them what happened. None of it makes any sense. People complain prisons are overcrowded, yet they threw people like Elaine in jail for life.'
Mrs Prince-Patron's spirits are flagging. She has had several visits from Foreign Office officials, but says the British authorities have done little to help.
'I'll be 79 when I first make it to the parole board, which is totally ridiculous,' she said, speaking by telephone from prison. 'I honestly don't believe that I'll live that long. Even then, it doesn't mean I'll make the board. My counsellor told me it could be 30 years. There is a time in your life when you give up hope. I have nearly reached that point.' There is, however, one ray of hope. Arizona has changed its laws since she was convicted. Had she been found guilty today, she is likely to have been jailed for seven years. A state 'parity review committee' is being set up to re- examine sentencing in previous cases. It will have the power to reduce her punishment, should it see fit.
Her lawyer is also working on an appeal, but it is likely to be several months before she finds out if her case will ever be reconsidered.
Meanwhile, she faces the prospect of missing many more of her grandchildren's birthdays for handling a soft drug which President Bill Clinton once smoked.