A senior director of MI5 is coming out of the shadows to become the new chief of GCHQ.

Jeremy Fleming, the deputy director-general of MI5, will step into a transatlantic storm over spying allegations this week when he is named as head of the government’s signals intelligence agency.

Last week GCHQ took the unusual step of publicly denying claims made by Donald Trump’s press secretary, Sean Spicer, who said it had spied on the property tycoon during the US election campaign. The agency called the claims “utterly ridiculous”.

Fleming’s appointment follows the resignation in January of Robert Hannigan for family reasons. Fleming has worked at MI5 for at least 20 years, part of which was spent on secondment to the Home Office. He also had