Observers of the US economy will be familiar with the so-called ‘Tiger effect’ – the recurrent phenomenon that when Tiger Woods, the world’s leading golfer, wins a tournament, business confidence surges and productivity goes up.

Now The Diary has discovered a strange new phenomenon sweeping the City – the ‘McGrath effect’ – whereby the productivity of UK law firms rises proportionately with each crushing defeat inflicted on the England cricket team by Ashes rivals Australia.