The line between the law and politics in Britain has never been clear: a decision by Jack Straw, the justice secretary, to grant a royal pardon to Michael Shields, the Liverpool football fan jailed for attempted murder in Bulgaria, has further blurred it, legal experts say.

Following decisions to drop a corruption investigation into alleged bribery in Saudi Arabia by BAE Systems and the release of Lockerbie bomber Abdelbaset Ali Mohmed al-Megrahi on compassionate grounds, some fear growing political interference in the justice system. Mr Straw himself has said the “quasi-judicial role” he has just played “is not a suitable function for the executive”.