In an interview with the Sunday Times, Wallace said the prospect of the US stepping back from its international role “keeps me awake at night”.

“I worry if the United States withdraws from its leadership around the world. That would be bad for the world and bad for us. We plan for the worst and hope for the best,” he said…

“Over the last year we’ve had the US pull out from Syria, the statement by Donald Trump on Iraq where he said Nato should take over and do more in the Middle East,” he said.

“The assumptions of 2010 that we were always going to be part of a US coalition is really just not where we are going to be.