Lawyers representing two of the four Britons released from Guantanamo Bay are pressing for their release as police continue interviewing the men.
The men are being held at Paddington Green station
The lawyers visited London's Paddington Green station and insisted there was insufficient evidence to detain them.
A fifth man, Jamal Udeen, was released without charge on Tuesday night, hours after the group arrived back in the UK.
The US released the men from prison in Cuba two years after their arrest in Afghanistan on suspicion of terrorism.
Ms Christian, whose client is Mr Dergoul, said she would argue for his release on Wednesday under the Terrorism Act, which allows for a review after 24 hours at 1900 GMT.
"My very strong view is that there is no basis whatsoever for holding Tarek Dergoul under the Terrorism Act."
She added: "I'm hopeful of getting him out, I don't think
there's any evidence against him."
Ms Peirce, who represents Shafiq Rasul and Asif Iqbal, said police were "compounding two years of injustice".
She said Tuesday night's procedures had gone on far too long, been unnecessary and protracted with fingerprinting continuing until after midnight.
"It was very clear that they should have been allowed to sleep long before
they were and it was very clear that their cells were too cold," she said.
Mr Rasul, 26, and Mr Iqbal, 22, are being held at the police station along with Ruhal Ahmed, 22, all of Tipton, West Midlands and Tarek Dergoul, 26, of east London.
But the National Co-ordinator for Terrorism, Deputy Assistant Commissioner Peter Clarke, said normal British law and procedures would be followed "to the letter."
A spokesman for Amnesty International told BBC News Online it would be in touch with lawyers of the men to check on the conditions of detention.
Publicist Max Clifford, who is representing Mr Dergoul, said the Briton had been in touch with his brother Halid Dergoul.
"Mentally, Tarek seems to be okay. Physically, he is in quite a bad way and
walking is a problem."
Meanwhile Mr Udeen's solicitor, Robert Lizar, said he wanted an apology from the UK authorities who were "complicit" in his detention.
The 37-year-old, reportedly reunited with his sister Maxine Fiddler, claimed he was questioned by MI5 officers in Cuba.
Mr Ahmed's father Riasoth told how his family was distraught at his son's arrest after two years being held as a detainee.
Speaking outside his home in Tipton, Mr Ahmed
said: "For 18 months, I have been saying he is not a terrorist. I want them to release my boy and I want to see my boy."
He continued: "Do you think my family's happy? My wife has been crying for the last 18 months and I am angry. They should let him go free."
He has still not managed to speak to his son since his release.
The men can be held for up to 14 days without charge under the Terrorism Act 2000.
Police will want to question them over alleged involvement in the commission, preparation or instigation of acts of terrorism.
The four men were arrested by the Metropolitan Police who boarded their flight at RAF Northolt in north west London shortly after it landed on Tuesday night.
They were examined by medical teams before being questioned.
Four other Britons - Feroz Abbasi, 23, Richard Belmar, 23, and Martin Mubanga, 29, all from London, plus Moazzam Begg, 36, from Birmingham - are still detained at Guantanamo Bay.
Home Secretary David Blunkett has indicated they will probably face trial in the US as they had been picked up "in the combat zone" in Afghanistan.
Moazzam Begg, a father-of-four, was arrested in the Pakistani capital Islamabad in February 2002.
A special edition of Panorama: Out of Guantanamo will be broadcast on Wednesday at 1930 GMT on BBC One