Liverpool car bomber from the Middle East

UK terror threat raised to SEVERE: Boris says Britain 'must remain vigilant' as it emerges Poppy Day 'suicide bomber was from Middle East and UNKNOWN to MI5' - as footage shows armed cops force man out of Liverpool home linked to hospital IED blast

• A taxi exploded as it pulled up outside Liverpool Women's Hospital yesterday, killing the one male passenger
• The explosion came at 10:57am, just before the 11am Remembrance minute's silence was due to be held
• Counter-terror police are leading the investigation amid fears the passenger who died was a suicide bomber
• Taxi driver David Perry was hailed hero by friends who said he locked the 'suspicious' man in his car
• Friends said that the passenger originally wanted taking to Liverpool's Remembrance Sunday service nearby
• Three men - aged 21, 26 and 29 - were arrested under Terrorism Act in raids in Liverpool yesterday afternoon
• Today fourth man, 20, arrested on suspicion of the same terror offence, close to property raided last night
• Mr Perry suffered relatively minor injuries and has already been released from hospital, friends have said