BY OUR SPECIAL CORRESPONDENT LONDON, Aug. 27: The police has arrested a 29-year-old man in Derby for suspected terrorism offences. The fifth arrest comes as part of an ongoing combined investigation by the Greater Manchester police counter-terrorism unit and the Lancashire constabulary into threats to kill Prime Minister Gordon Brown and his predecessor Tony Blair. Three men of Asian origin were arrested on August 14 on suspicion of committing offences under the Terrorism Act 2006. Two men were arrested at Manchester Airport just as they were about to board a flight to Finland and one at Accrington in Lancashire on evening of August 14. Fourth suspect, identified as a 25-year-old white convert to Islam in most newspapers, was arrested on Tuesday morning at Blackburn in Lancashire. The fifth arrest in the case was made in Derby, Derbyshire, on Tuesday by the Greater Manchester police. A search of the address in Derbyshire is underway and is expected to take several days, the police added. Last Wednesday, the Lancashire police was granted an additional seven days to question the three men, whose identity has not been made public as yet. The three men belong to Blackburn in Lancashire and are aged 21, 22 and 23 years, the Lancashire police said. The three men had been arrested in connection with a statement posted on a website by a group called "Al Qaeda in Britain," which demanded the withdrawal of British forces from Iraq and Afghanistan. Provided by