The mother of a British man accused of drug offences in Dubai has spoken of the "horror story" of his alleged torture by police.
A Dubai judge is to give a verdict on Monday in the trial of Grant Cameron and fellow Londoners Suneet Jeerh and Karl Williams. They all deny charges.
Tracy Cameron told the BBC the three, who say they were given electric shocks, had been "treated appallingly".
Police in the country have denied any wrongdoing.
The three men, who are charged with possessing, taking and intending to distribute illegal drugs, were arrested on holiday in August after police said they found a quantity of synthetic cannabis known as "spice" in their car.
Legal rights charity Reprieve said the charges should have been dropped and the men - who went on trial in February - should be released because of the torture allegations.
Meanwhile, the UK Foreign Office has called for a full, independent and impartial inquiry into the allegations and says it has raised them with "very senior officials" in the United Arab Emirates.
Ms Cameron said her son and his friends were put through "a pretty terrifying ordeal" after they were arrested.
"They were taken back to their hotel room, they were beaten in their hotel room, it does appear they were separated from each other and each taken to a different room," she told the BBC.
"Karl was laid out on the bed, his trousers were stripped down and electric shocks were administered to his testicles while he was blindfolded.
"I believe all boys had guns held to their head - they were told they were going to die.
"Grant sustained electric shocks to his torso and I believe Suneet had shocks administered to him to the back of his head and his back."
She said all the men were pressured into signing statements written in Arabic which they did not understand.
When her son told her of the torture in a phone call, Ms Cameron said she felt "beside myself, sheer horror, terror, just complete and utter meltdown really".
"Your son being arrested so far away from home is challenge enough to deal with but, once he told us how he'd been treated, I can only describe it as something from a horror story."
She said she had been told by lawyers her son was likely to be found guilty of at least one of the charges and could be jailed for 15 years or longer.
Reprieve's Kate Higham said torture by Dubai police was "hugely common" and the charity believed the men's "extremely plausible" account.
It was backed up by notes from Foreign Office staff who had visited the men and documented their injuries, she said.
"We've shown these to a doctor who's an expert in the assessment of torture and he's said that the injuries are consistent with the torture that the men described," she added.
She said that, if British experts were allowed access to the men, a simple diagnostic test would "very easily" prove they had been tortured.
However, Doctor Abdul-Kallek Abdulla, a professor of political science in the UAE, told BBC Radio Five Live there was no proof to support the torture claims and "absolutely no truth" to the allegations heard in the British media.
He said: "You could say whatever you want but I go by official statements. The UAE is not a country which practices these things."
Meanwhile, a coalition of campaigners has urged Prime Minister David Cameron to challenge the human rights record of the United Arab Emirates during a state visit by the country's president, Sheikh Khalifa bin Zayed Al Nahyan later this week.
The coalition - comprising seven human rights organisations, including Amnesty International - has written to the prime minister urging him to raise the issue of alleged abuses.
BBC world affairs correspondent Richard Galpin said there would be a chance for British officials to discuss the case with the UAE president.
But foreign policy and bilateral trade issues would be at the heart of formal talks with the government, our correspondent added.
Ms Cameron said she hoped the president would listen: "I sincerely hope that he is able to look into the case and show a level of clemency to the boys because, sincerely, that's what needs to happen in this case and hopefully, once he's made aware, he can make that happen."