Exclusive: Role as permanent undersecretary comes amid return of Donald Trump and wars in Ukraine and Middle East

The former Brexit negotiator Oliver Robbins has been appointed as the UK Foreign Office’s most senior civil servant, taking over from Sir Philip Barton.

Robbins, who was on the shortlist last year but failed to get the civil service’s top job, was believed to be David Lammy’s favoured candidate for the role of permanent undersecretary.