Boris Johnson ally Nigel Adams has said he is standing down as an MP with “immediate effect”, triggering another by-election.

The move, which follows the former prime minister’s resignation on Friday, will leave Prime Minister Rishi Sunak facing a third by-election – this time in Mr Adams’s Selby and Ainsty constituency.

He previously said he would quit at the next general election but has joined Mr Johnson and Nadine Dorries in resigning now.

It follows Boris Johnson’s scathing 1,000-word resignation statement in which he claims a “witch hunt” is under way to “take revenge for Brexit”.

He was also critical of Mr Sunak and said the Conservatives’ gap in the polls has “massively widened” since he left Number 10.

The Conservatives won the North Yorkshire constituency in 2019 with a majority of 20,137.

A new parliamentary candidate was selected by Selby Conservatives on Friday ahead of the next General Election and Mr Adams informed the chief whip on Saturday that he would stand down immediately.

Mr Adams was first elected as MP for Selby and Ainsty in 2010 and has held several positions in government under both Theresa May and Boris Johnson.

In a statement, Mr Adams said: “Yesterday, Selby Conservatives selected an excellent new parliamentary candidate.

“I’ve today informed the chief whip that I will be standing down as a Member of Parliament with immediate effect.

“It has been an honour to represent the area where I was raised, educated.

“I want to thank my constituents for their wonderful support since 2010.”