Tony Blair warned Donald Trump’s aides that British intelligence agencies could have spied on them during the election campaign, a new book has claimed.

The former prime minister shared the “juicy rumour” with Jared Kushner, Mr Trump’s son-in-law, when the pair met last February, according to journalist Michael Wolff’s book.

Mr Blair suggested the British “had the Trump campaign staff under surveillance, monitoring its telephone calls and other communications and possibly even Trump himself”, an extract said.

But Mr Blair has dismissed the claim as a "complete fabrication".

The meeting is said to have come as Mr Blair sought a new role in the Middle East after Mr Trump entered the White House.

The claim is one of a series of explosive allegations in Mr Wolff’s book, called Fire and Fury: Inside the Trump White House.