David Cameron asked Barack Obama to warn that the UK would go to "back of the queue" for a trade deal after Brexit, a former White House adviser has said.

The then-US President made the remark at a press conference with Mr Cameron, the then-Prime Minister, just weeks before the in/out referendum in April 2016.

There was intense speculation at the time that the remark may have been scripted by Number 10, because the expression “back of the queue" is rarely used by Americans, who tend to prefer the phrase "back of the line".

Downing Street insisted at the time that the then-US president was using his own words when he made the comment during a press conference with Mr Cameron in the run-up to the EU referendum in 2016.

The denial was repeated by Sir Craig Oliver, Mr Cameron’s former communications director, who said in a memoir “There’s some weird whinging from the Leavers that the fact that he said ‘queue’ instead of ‘line’ proves it was written by No 10. I slap it down. ‘Nonsense. The President can speak for himself’."