British authorities have detained 10 foreigners considered a threat to national security, including Muslim cleric Abu Qatada.
A government official, who spoke on condition of anonymity, confirmed that the Palestinian cleric described by British officials as Osama bin Laden's "spiritual ambassador in Europe," was in custody.
"People have been whisked off to prison and we are being denied access to them," said Abu Qatada's lawyer Gareth Peirce. "Now it's suddenly fine to deport people who for years the government has said it was unsafe to do so. It's quite extraordinary."
Prime Minister Tony Blair has been under pressure to take tough action against foreign nationals who incite terrorism, after four bombers killed themselves and 52 other people in attacks on London's transport system on 7 July, reports Aljazeera.
The BBC said the group includes Abu Qatada, a Jordanian-Palestinian, accused by Spain's top judge of being the spiritual inspiration for the September 11 plotters. Britain has called him a "dangerous individual".
The government spelled out plans last week to deport hardline Islamists who it believes are inciting or glorifying militant attacks and has signed bilateral agreements with a number of countries to return them.
"We now have good reason to believe that we can get necessary assurances from the countries to which we will return the deportees so that they will not be subject to torture or ill-treatment," Home Secretary Charles Clarke said.
Clarke said in a statement the presence of the 10 foreign nationals was "not conducive to the public good".
He said the men were held on Thursday by immigration officers backed by the police under existing powers available to him under the UK's Immigration Act.
"The circumstances of our national security have changed, it's vital we act against those who threaten it," he said. "They will be held in secure prison accommodation and I will not disclose their names."
The government rushed through laws after the September 11, 2001, attacks on the United States, giving police the power to hold foreign terrorism suspects indefinitely without charge or trial, informs Reuters.