France is reportedly hoping to take Britain's senior position in Nato amid claims the UK's role within the alliance could be at threat after Brexit.

A Briton has held the position of deputy supreme allied commander – the No 2 military post in the alliance – since 1951 but this may have to be transferred to a member of the EU under options being discussed, the Royal United Services Institute (Rusi) said.

The role is central to securing Nato manpower and equipment for certain EU missions organised under so-called "Berlin-plus" arrangements.

“There is already some discussion of the possibility that the assignment of the position . . . might have to be transferred to a Nato member that is a member of the EU,” Rusi deputy director-general Prof Malcolm Chalmers wrote in a briefing on the UK's post-Brexit foreign and security policy.