The father of a Briton held in Guantanamo Bay has welcomed a US court decision to allow prisoners to challenge their detention.
Moazzam Begg remains in Guantanamo
Azmat Begg said he will take legal action against his son Moazzam's continuing detention if he is not released from the Cuban base.
Meanwhile two Britons released from Guantanamo in March have called for detainees to be told of the new rights.
Shasiq Rasul and Asif Iqbal warned it was unlikely prisoners would be told.
The US Supreme Court has ruled terror suspects held there can use the US legal system to challenge their detention.
Hundreds of appeals on behalf of the more than 600 inmates could start to make their way through the court system as a result.
Feroz Abbasi, 23, Richard Belmar, 23, and Martin Mubanga, 29, all from London, as well as Moazzam Begg, 36, from Birmingham - are still detained at Guantanamo Bay.
Lawyer Louise Christian, who represents Mr Abbasi and Mr Mubanga, said the decision would not see her clients freed in the near future, but urged the UK Government to keep up pressure on Washington.
Mr Begg has pursued a high-profile campaign to free his son.
His son has been in American custody since he was arrested in Islamabad, Pakistan, in February 2002.
Mr Begg told BBC News Online he was pleased with the US Supreme Court ruling.
"It was what we were expecting. Our feeling was always that we are right and the government is doing wrong.
"It's against democracy, human rights and the process was not being done properly," he said.
If Moazzam Begg is not freed as a result of the ruling, the family would take legal action, said his father.
The action would be "against detention - keeping them in custody for two-and-a-half years - and against the torture.
"And torturing the father, mother and everybody - the whole family has suffered very badly."
Moazzam Begg is believed to have been arrested by the US in Pakistan as a suspected al-Qaeda or Taleban fighter.
But campaigners say the law student was in Afghanistan to teach children, rather than to fight American and British forces.
Meanwhile former detainees Mr Rasul and Mr Iqbal gave the decision a cautious welcome.
The pair, from Tipton, in the West Midlands, were freed two years after their arrest in Afghanistan on suspicion of terrorism.
They said they were sceptical the new access would become a reality, as "despairing" prisoners will not find out about their new rights.
Their own release, with three other Britons, came only because their case was due in the US Supreme Court, they believe.
'We are sure that not one of the hundreds of prisoners held unlawfully at Guantanamo Bay will be told of today's decision," they said in a statement.
"For the whole of the 26 months we were detained there, we were told 'You have no rights, this is Cuba'."
Instead, they said, they were left in constant "mental pain, high anxiety and physical discomfort".
Fearing for the "many detainees who already will have slipped over the precipice of despair", they appealed to the US Government.
"Give a public undertaking that each detainee will be told today that he has a right of access to the US courts and be provided today with a lawyer to make that access a reality," they said.