The Government does not know the full extent of the leak of Sir Kim Darroch's emails, it has said.

Sir Alan Duncan, foreign minister, told MPs he did not know if there were other emails "in the wrong hands" which could be leaked at some point.

"In terms of the emails that have been leaked they are two years apart - one cluster very recent and one of two years ago," he said.

"So it is not quite right to say they have been leaked consistently throughout that period.

"But of course we don't know if there are any others in the wrong hands which might subsequently be leaked".

Sir Alan added that the Cabinet Office would "use all of the means it can to delve into this and try find a culprit".

He said that if they discover who is behind the leak that person would "regret the moment for the rest of their life".

It comes after Theresa May said she has "full faith" in Sir Kim and would not apologise to Donald Trump for the ambassador's attack on the "inept" US president.