Ministers are facing calls to intervene on behalf of an Australian held as a terrorist suspect at Guantanamo Bay after he won a four-year legal fight to become a British citizen.
To the Government's embarrassment, the High Court ruled that Charles Clarke, the Home Secretary, had "no power in law" to deprive David Hicks of his citizenship "and so he must be registered".
Mr Hicks, often described as the "Australian Taliban", has been held at Guantanamo since January 2002 after being picked up by US forces in Afghanistan.
He denies charges being prepared against him of conspiracy to commit war crimes and of aiding and abetting the enemy. The American authorities have accused him of attending terrorist training camps in Afghanistan and Pakistan.
Mr Hicks, 30, applied for UK citizenship as his mother was born in Britain before emigrating to Australia as a young girl.
After the High Court found in his favour yesterday, his lawyers said that they would press the Government to make arrangements for him to take the required citizenship oath and pledge.
Although Mr Justice Collins gave the Home Secretary permission to appeal, he refused to suspend the appeal. The Government described the ruling as disappointing.
Mr Hicks' lawyer, Stephen Grosz, said he will urge the Home Office to seek Mr Hicks' release from the detention camp in Cuba and for him to be brought to the United Kingdom. Mr Hicks says the Australian government has refused to plead for his release and prevent his trial by a US military commission.
Louise Christian, a human rights lawyer, said: "If he has got British citizenship then the Government will be obliged to do the same for him as they did the others. He would be the only British citizen at Guantanamo Bay.
"I would be prepared to go to court for him. But it took a long time to get the others back. The others who came back were only returned after protracted negotiations."
Mr Hicks' father, Terry, said: "Hopefully the British Government may look at it as David's another British citizen held at Guantanamo. They do have a ruling with the Americans that none of their citizens will face military commissions, so they may ask for David to be released into their custody."
Mr Clarke argued citizenship should be refused because of Mr Hicks' alleged involvement with al-Qa'ida.
Clive Stafford-Smith, a lawyer working on the case, said after the ruling: "The British Government is mandated to take action."
Mr Hicks visited Albania in 1999 where he joined the Kosovo Liberation Army for a short spell before returning to Australia.
He converted to Islam, began studying Arabic, then travelled to Pakistan where he took up religious studies. From there he travelled to Afghanistan, where he was picked up by US forces.
Mr Hicks, from Adelaide, has claimed that he was subjected to regular abuse in Guantanamo. He has said he was beaten while being handcuffed and blindfolded, had his head slammed into concrete and was forced to run in leg shackles.
In an affidavit, he says that he was offered - and he refused - the services of a prostitute if he agreed to spy on other detainees. The Australian Attorney General has cast doubt on these claims.
Nine British citizens held in Guantanamo Bay have been released in the past two years. However, another five UK residents remain in the military camp.Reuse content