Labour and the Conservatives spent Thursday trading accusations over asylum following the conviction of Kamel Bourgass, an illegal immigrant and al Qaeda terrorist, for plotting a poison attack on Britain.

He had earlier been convicted of the murder of Stephen Oake, a Manchester detective involved in his arrest two years ago.

Alan Milburn, Labour's campaign co-coordinator, apologised for DC Oake's death.

He told ITN News: "Of course what we apologise for is the death of that police officer, serving his country, trying to protect his country.

"The issue now is how we ensure that sort of thing does not happen again."

Michael Howard directly linked Labour's "asylum shambles" to Oake's death.

The Conservative leader said: "To pretend ID cards are the solution to failed asylum seekers is deceitful and that tells us everything you need to know about this government.

"It will do anything and say anything to try to get re-elected. People are fed up with this kind of behaviour."

It has also emerged that Algerian suspects in the ricin poison plot are being allowed to stay in Britain despite using false identities and passports.