Lord Ashcroft, the Conservative peer and former party Treasurer, is suing two cabinet ministers whose departments he accuses of conducting a "dirty tricks" campaign against him.

Jack Straw, the foreign secretary, and Clare Short, the international development secretary, are named in a writ filed in the High Court on Friday.

Lord Ashcroft, who faced a barrage of criticism over his business affairs in Belize, is suing the government claiming it infringed his right to privacy by failing to stop official documents concerning him being leaked to the press.

The ministers will fight the claims, arguing that they cannot be held personally responsible for leaks to newspapers.