By ROBERT BARR
Associated Press Writer
LONDON (AP) - Britain served deportation orders Thursday on seven men who were detained as threats to national security, including some accused of a terrorist plot to spread the poison ricin.
The Home Office confirmed that the men were detained in London and Manchester. They were being held under the government's powers to deport people ``whose presence in the U.K. is not conducive to the public good for reasons of national security,'' the Home Office said in a statement.
Officials declined to disclose the names or nationalities of the seven.
A senior government official, however, confirmed to The Associated Press that some of those detained had been previously charged with participating in a terrorist plot involving the poison ricin.
Four Algerians were acquitted in that case in April, and prosecutors dropped charges against three other Algerians and a Libyan. The official, who spoke on condition of anonymity because of the sensitivity of the issue, declined to discuss how many of Thursday's detainees had been acquitted in the ricin case or their nationalities.
The Home Office declined to say what had prompted Thursday's sweep. However, in recent months the government has been trying to reach agreements with several countries, including Libya and Algeria, guaranteeing that detainees would not be tortured or mistreated if deported there.
The only man convicted in the ricin case, Algerian Kamel Bourgass, is in prison serving a life sentence for murdering a police officer. He was also sentenced to 17 years for conspiracy.
Gareth Peirce, an attorney who represented some of the ricin defendants, was unavailable for comment, her office said.
The senior official stressed the men had been detained under the 1971 Immigration Act, not under the new powers introduced last month to deport radical Islamic preachers and others who incite or glorify terrorism. The official said the men were not Islamic clerics.
Police said they found recipes for ricin, cyanide and botulinum, and the blueprint for a bomb, when they raided an apartment in London two years ago.
Ricin is derived from the castor bean plant and is one of the world's deadliest toxins. It has been linked in the past to Osama bin Laden's al-Qaida terror network and Iraq. It has no known vaccine or antidote and kills cells by preventing them from making proteins.
The individuals will be held in prison pending deportation proceedings, the Home Office said.
Earlier in August, Britain detained 10 foreign residents, who included Omar Mahmoud Othman Abu Omar, also know as Abu Qatada - a radical Muslim preacher previously described by Spanish officials as bin Laden's ``spiritual ambassador in Europe.''
Britain also barred another radical Muslim cleric, Omar Bakri Mohammed, from returning to the country.
The crackdown followed the July 7 bombings that killed 52 bus and subway passengers and four suicide bombers in London, and the failed attacks two weeks later.
The Home Office said the detainees had five working days to appeal against deportation - a process that could drag on for months.
As a signatory to the European Convention on Human Rights, Britain is not allowed to deport people to countries where they may face torture or mistreatment. Britain has been trying to sign agreements guaranteeing humane treatment of deportees with 10 countries, including Algeria, Lebanon, Egypt and Tunisia. The first such memorandum was signed with Jordan last month.
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Associated Press reporter Ed Johnson in London contributed to this report.
In dawn raids ordered by the UK Home Secretary, Charles Clarke, seven people have been detained in London and Greater Manchester.

The seven, who are believed to all be Algerian, are thought to include some of those allegedly involved in an earlier ricin poisoning plot.

The Home Secretary ordered the raids based on information provided by police and other security forces.  Those seized may appeal against deportation, but are deemed a "threat to national security" by the Home Office.  According to officials, those detained were done so using powers granted under the Immigration Act of 1971, not under the recently passed legislation aimed at removing radical muslim clerics from the country.