Four of the five British men released
from Guantanamo Bay have been arrested and taken to a London police station.
The police convoy arrives at Paddington Green police station
The US released the five - held in Cuba as terrorism suspects for two years - saying they presented a low risk. They landed at RAF Northolt at 1900GMT.
The fifth man, Jamal Udeen, was interviewed at the airbase before being released shortly before 2200GMT.
His solicitor said Mr Udeen believed the UK government was 'complicit' in his detention in 'inhumane' conditions.
Robert Lizar said: "He's looking forward to seeing his family very much. However he wants the US authorities to answer for the injustice which he has
"He has been detained as an innocent person for a period of two years. He has been treated in a cruel, inhumane and degrading manner, he wants the authorities to answer for that.
"He believes that the UK authorities have also been complicit in terms of
being involved in questioning him while in detention and allowing that to
Mr Udeen urged people to raise the plight of those still being detained in Cuba with the US and UK authorities, Mr Lizar added.
The five men who returned on Tuesday were Shafiq Rasul, 24, Asif Iqbal, 20, and Ruhal Ahmed, 21, all of Tipton, West Midlands, Jamal Al-Harith - also known as Jamal Udeen - 35, of Manchester, and Tarek Dergoul, 24, of east London.
Uniformed police officers acting as an escort team on behalf of the government and two independent observers, including one from the Muslim community, accompanied them on the flight.
But the men were not restrained on the plane and the entire flight was videoed.
The Metropolitan Police boarded the flight at Northolt and arrested four of the men under section 41 of the Terrorism Act 2000.
They were taken to Paddington Green high security police station in central London in two armoured police vans.
Under the provisions of the Terrorism Act the men can be held for up to 14 days without charge.
They will be interviewed by officers from the Metropolitan Police Anti-Terrorism branch over alleged involvement in the commission, preparation or instigation of acts of terrorism.
The National Co-ordinator for Terrorism, Deputy Assistant Commissioner Peter Clarke, said: "Everything that happens to these men from the moment they entered UK territory is entirely in accordance with British law and the normal procedures will be followed in this case to the letter.
He explained this means the former Guantanamo prisoners will be given access to legal advice and are entitled to a telephone call.
The Muslim Council of Great Britain has issued a statement welcoming the return of the British detainees.
"We understand that the police may yet bring charges against these men. It is crucial that if this happens, the men be given a fair trial and are allowed to defend themselves in a court of law," it said.
US Defence Secretary Donald Rumsfeld defended the decision to send the five home to the UK.
He said: "We got what we needed out of this crowd of five people, let's move them along!"
But he suggested the system was not faultless and said: "Of the people who've been released, we know of one who's gone back to being a terrorist. Life isn't perfect."
Speaking in the US on Monday, Home Secretary David Blunkett indicated four other UK detainees would probably face trial in the US as they had been picked up "in the combat zone" in Afghanistan.
The four remaining men are Feroz Abbasi, 23, Richard Belmar, 23, and Martin Mubanga, 29, all from London, plus Moazzam Begg, 36, from Birmingham.