What will happen to those linked to the London 'poison' factory?

Who was seized by police and immigration officials yesterday morning?

Seven Algerians were held in dawn raids in London and Manchester. They were taken to prison and now face expulsion from Britain on the ground that they are a threat to national security.

Who are they?

It is understood that six of them are linked to an alleged plot, centred on a flat in Wood Green, north London, to release ricin. Eight men were acquitted in April of plotting to manufacture the deadly toxin; four were found not guilty and the other four acquitted after the prosecution offered no evidence.

What will happen to them now?

They face deportation to Algeria, despite fears that they could be tortured upon their return there. The Government has been trying to reach a memorandum of understanding with the north African state that they would not be abused, but has not yet completed it. Lawyers for the men are certain to challenge their removal in the courts.

Why did the ricin prosecutions fail?

Because of the failure to find any ricin in the raid in January 2003 or to demonstrate any conspiracy to release it. It is indeed a mystery why the prosecutions ever came to court.

Five of the suspects were jailed for passport offences and have only recently been released. The suspicion is that their details were passed to police and immigration officials by MI5.

But didn't the Government use the alleged ricin plot as evidence of a continuing terrorist threat?

The week after the Wood Green flat was raided and the month before the Iraq war, Tony Blair cited the alleged plot as "powerful evidence" of the terrorist threat. Colin Powell, the former US Secretary of State, advanced the same argument as he made the case for war in Iraq.

The Liberal Democrats said yesterday that the connection was "central" to the case for war and demanded an investigation into why the failure to find ricin was not admitted by the authorities.

Who was to blame for failure to admit there was no ricin in the flat?

The Defence Science and Technology Laboratory, a Ministry of Defence agency. In an admission that means Tony Blair cannot be accused of misleading the public, it confessed that it failed to tell detectives, or the Government, that no trace of ricin had been found until 20 March 2003 because of a "breakdown in procedures".

That date rings a bell...

It was the day that the invasion of Iraq began.

Is it another coincidence that yesterday's arrests came as the Home Office announced a fresh batch of anti-terrorist legislation?

The Government says so, but it was a still happy coincidence to give a concrete demonstration of the authorities acting tough.

Why are they needed when there are already more than 200 pieces of anti-terrorist legislation on the statute books?

The Government says they help plug gaps that opened because of the changing nature of terrorism. Critics have accused ministers of hyperactivity following the London bombings to be seen to be doing something. However, most of the proposals will receive unanimous political support.