So, David Laws appears to have been a member of the Cabinet for 18 days.

But whose was the shortest stint? There’s a lot of history to sift through, but Twitter has come to my aid.

Fox Maule was President of the Board of Control for 16 days in 1852 (5th to 21st February)

Thomas Milner Gibson was President of the Poor Law Board for 16 days in 1859 (24th June to 9th July), but then went on to become President of the Board of Trade, so stayed in the Cabinet.

Sidney Herbert was Secretary of State for the Colonies for 15 days in 1855 (8th-23rd February).

James Waldegrave, 2nd Earl Waldegrave was de facto (though the term did not yet exist) PM for 4 days in 1757 (8th to 12th June).

Earl Temple was Home Secretary and Foreign Secretary for 4 days in 1783, two of which were spent finding his successors.

William Pulteney, 1st Earl of Bath was de facto PM for 2 days with Carteret as Secretary of State in 1746 (10th-12th February). According to Wikipedia, the exact figure is 48 hours, 52 minutes, 11 seconds.

However, the unclear winner seems to be Robert Peel in 1839. He certainly accepted the Queen’s invitation on 8th May, but she asked Melbourne back the following day when she refused his proposed changes to the Royal Household. He would thus have been PM for about a day, and thus a member of the Cabinet.

The problem with this episode, as well as the 1746 Bath ministry is that they hardly count. Depending on your pedantry however, the safest winner would be Earl Temple with his 4 days in control of two of the largest departments. Poor guy.

According to the excellent Tim Roll-Pickering, the briefest ministerial (if not Cabinet) career was that of Lord Frederick Cavendish, appointed Chief Secretary for Ireland on 6th May 1882, and murdered that same afternoon.

A similar ministerial non-Cabinet career was that of George Cowper, who was Parliamentary Under-Secretary to the Foreign Office from 13-14th November 1834.

(Thanks go to Tim Roll-Pickering, James Burdett and Ian Burgess for helping me out via Twitter)