The mother of a north London man jailed in Egypt for 25 years for drug trafficking offences claims he was pressured into confessing his guilt.
Pierre Wassef, 30, from north London, was arrested in Cairo in October 2007, and confessed to trafficking large quantities of cocaine.
Sue Wassef claims her son was coerced into confessing by Egyptian officers.
She said officers told him his younger brother would face the death penalty if he did not admit to the crime.
Pierre Wassef was arrested with his younger brother Philippe, who is now 27, in a shopping centre in a Cairo suburb.
Ms Wassef, told BBC Radio 5 live's Victoria Derbyshire show: "Nothing was found on either boy and nothing was found in the car."
Police claimed to have found cocaine in Pierre's house, which they alleged was intended for sale.
However, Pierre and his brother maintain that to their knowledge there were not any drugs in the house.
The mother described the police interrogation she believes the men went though.
"Philippe was tied to a stairwell. I believe Pierre was chained to a radiator," she said.
"They were denied water, food or any toilet facilities.
"Every time Philippe or Pierre closed his eyes they would slap them so they couldn't sleep."
Pierre "was forced to make a statement", Ms Wassef said.
"He was told that if he didn't cooperate with police, his younger brother would take the hanging sentence."
Philippe was released several days after his arrest but Pierre was sentenced to 25 years in jail.
Pierre Wassef has since withdrawn the confession and maintains that he is not guilty of any crime.
Mr Wassef is currently being held in a prison in Alexandria, in north Egypt.
His mother said: "There are 30 people to a cell. There are no fans. You're allowed a 15 minute visit once a fortnight."
"I haven't seen him since February. He's quite depressed. He hasn't seen his children in three years," she added.
Ms Wassef said she was "desperately trying to ask the embassy to help us get him back to Cairo" and she has set up an online petition."
The Foreign Office says that it "continues to provide consular assistance in this case and remain in close contact with the family."