Police in Britain were searching the home of a man arrested Tuesday under terrorism laws, days after the government raised its threat level to severe, suggesting an attack was 'highly likely'. The 30-year-old man was held in Birmingham, central England, on suspicion of possessing material likely to be of use to a terrorist and of distributing terrorist publications. The arrest under the Terrorism Act came 'as a result of a long, detailed and ongoing inquiry,' according to the officer in charge of the investigation, Detective Superintendent Kenny Ball. The home of the man, who has not been named in line with police policy, and another address in the city are currently being searched. Home Secretary Alan Johnson announced Friday that Britain was raising its terror threat assessment level from substantial to severe, four weeks after the attempted bombing of an airliner approaching the US city of Detroit. 