Policeman's death stuns Britain

British police interrogated three North African suspects yesterday after a policeman was stabbed to death during an anti-terrorism operation linked to the discovery of a deadly poison in London.

Shocked by the first loss of an officer in dozens of post-September 11 swoops on suspected terror cells, Prime Minister Tony Blair's government said the incident had "major implications" for its wider war on terror.

Addressing parliament in a sombre mood, Blair said: "It reminds us of the threat that international terrorism poses here in Britain and of the need to take all the measures we possibly can to stamp it out in all its forms."

Detective Stephen Oake was stabbed to death with a kitchen knife late on Tuesday during a raid in Manchester, northern England, connected to last week's discovery of ricin in London. Four other police officers were injured. Blair - whose nation is considered high on the list of terrorism targets because of its military and political support for the United States - called the incident "an appalling tragedy and wicked in the extreme".

Oake was known to the prime minister after serving in his protection unit several times.

The Manchester raid was the latest in a string of British anti-terror swoops in recent months, from the southern coastal town of Bournemouth to the Scottish capital, Edinburgh.

More than 200 people have been arrested in Britain under anti-terror legislation since September 11, 2001, with several dozen currently awaiting trial. Most are north Africans, with the majority coming from Algeria.

"This matter has major implications in terms of our anti-terrorism crime and security act," Home Secretary (interior minister) David Blunkett said. "This threat is a continuous and dangerous one."

Critics were quick to question why the suspects were not handcuffed and the officers unarmed.

Manchester Police Assistant Chief Constable Alan Green said an internal review into the operation was already under way and made a plea for no reprisals against local Muslims.

No toxin was found in the Manchester apartment, but forensic officers continued to search the property, where well-wishers left flowers and cards.

Residents said the Crumpsall neighbourhood's transient and multi-ethnic population made it an ideal area to hide away. "To be quite honest, it's a perfect place for anybody planning something nefarious," Rabbi Arnold Saunders said.

Key terrorism arrests in Britain

Terror fears in Britain are on the rise following a series of high-profile arrests. Following is a chronology of recent cases.

January 12: Anti-terror police arrested five men and one woman in the seaside town of Bournemouth and British media reported that the arrests were linked to the London ricin case.

No chemicals were found and police released the six without being charged.

January 5: Seven North Africans were arrested after traces of ricin were found in a north London flat.

Four men were charged on terrorism offences and will appear at the Old Bailey central criminal court on January 17.

December 18, 2002: Seven Algerians were arrested in Edinburgh and London.

Six are due to appear for trial on terror charges but no date has yet been set.

November 9, 2002: Three North African men were charged under the Terrorism Act for possession of articles for the preparation, instigation and commission of terrorism.

British newspapers said the men had planned a cyanide gas attack on London's Underground system. They are expected to reappear in court on January 20.

January 20, 2002: Two Algerians from Leicester appeared charged with an array of offences under the Terrorism Act. Both were accused of being members of bin Laden's al-Qaeda network and financing terrorism.