Tory MP and Boris Johnson ally Nigel Adams stands down, triggering a third by-election

One of Boris Johnson’s closest allies, Nigel Adams, has become the third Conservative to quit as an MP in just under 24 hours, triggering a by-election in his Selby and Ainsty constituency.

Plunging Rishi Sunak into further turmoil, Mr Adams announced on Saturday afternoon that he would be standing down with “immediate effect”.

It comes a day after Mr Johnson stood down as MP for his Uxbridge constituency ahead of the publication of the Commons’ partygate probe.

The former PM’s shock resignation was preceded just hours earlier by the resignation of his close ally and Mid Bedfordshire MP Nadine Dorries.

Making the announcement on Twitter, 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 and I want to thank my constituents for their wonderful support since 2010.”

Mr Adams had said last year he would not be standing in the next general election and the constituency party had already selected a candidate, Michael Naughton, to stand as its candidate.

But a fresh announcement by Mr Adams on Saturday that he would now be leaving immediately means there will now be a by-election in his North Yorkshire constituency.

This story is being updated.