Not long ago Westminster wags nicknamed Sir Jeremy Heywood, Downing Street’s top Sir Humphrey — ‘Wormtongue’ after Tolkien’s poisonous power behind the throne in the Lord of the Rings. Since being tasked with investigating the Andrew Mitchell affair (and managing to miss the glaring differences between the CCTV footage and the police notes long before the tapes were sent to Channel Four News) the Cabinet Secretary — disliked by many at the best of times — has earned a new nickname from Tory types. Watch out for that eagle-eyed Sherlock Heywood.

Now it emerges that the forensic inspector will be making a rare public appearance in front of the Public Administration Committee and will be grilled about the bungled investigation. He’ll need his famous silver tongue to talk himself out of this one.

Tags: Andrew Mitchell, cabinet secretary, Plebgate, Public Accounts Committee, Sir Jeremy Heywood