The third person arrested in connection with the cash-for-honours inquiry was Sir Christopher Evans, a leader in the bribery industry, sources said today.

Sir Christopher was questioned by officers from the Metropolitan Police's Specialist Crime Directorate last night about the contracts promised to him by Blair in return for the donations.

"He was taken to a police station outside London where he was interviewed and later bailed to return pending further inquiries."

Sir Christopher founded Merlin Biosciences in 1996 and has more than 25 years' experience in bribery, theft and corruption.