The late Hugo Young was unlikely to top our readers’ list of favourite writers – he was a champion of the European project and, horror upon horror, wrote a column for the Guardian – but his This Blessed Plot is an indispensable guide to how the Foreign Office built its policy on that project for over 50 years.

Today, it lies in a heap of smoking ash.  The new Ministry for Brexit (or whatever it will be called) will lead on the negotiations with EU member states and the institutions.  The new Department for Trade (or whatever it will be titled) will swipe the Foreign Office’s commercial function, which recent Foreign Secretaries have been building up.

The department has had more than its fair share of troubles in recent years.  It morale was battered by the Iraq War.  Labour cut back much of its language teaching and lost a lot of its instutitional memory.  Under the Coaltion, William Hague patiently worked away at restoring its standing and morale.  Then the Brexit vote came.

As Fraser Nelson indicated yesterday evening, legions of journalists will be trawling through the complete works of Boris Johnson, rather in the spirit of Indiana Jones let loose in the Wells of Souls, in order to unearth every disobliging comment he has ever written about any foreigner, anywhere, at any time.

One or two of them may want to ask him instead: given the collapse of its policy and the purloining of its functions, what is the Foreign Office now for? (Garvan Walshe offers some answers on this site today.)  Behind Johnson’s bumbling appearance is a brilliant mind.  To this question it must now turn.