The Treasury has confirmed today that Conservative Mid Bedfordshire MP Nadine Dorries has formally resigned her seat, leading to a by-election in the constituency.

Under parliamentary process, Chancellor of the Exchequer Jeremy Hunt had to appoint her to be Steward and Bailiff of the Three Hundreds of Chiltern. This is the traditional mechanism for leaving the House of Commons.

But there could still be several weeks before polling day, as the earliest date is expected to be Thursday, September 28.

A motion, known as a writ, has to be moved when Parliament returns on September 4, which allows between 21 and 27 working days for a by-election.

Former government minister Ms Dorries was critical of Prime Minister Rishi Sunak in her resignation letter, reported in a national newspaper.

“What exactly has been done or have you achieved?” asked Ms Dorries. “You hold the office of Prime Minister unelected, without a single vote, not even from your own MPs.

“You’ve no mandate from the people, and the government is adrift. You’ve squandered the goodwill of the nation, for what?

“Since you took office a year ago, the country is run by a zombie parliament where nothing meaningful has happened.”

Mentioning her constituents in the resignation letter, she said: “It’s been the greatest honour and privilege of my life to have served the good people of Mid Bedfordshire as their MP for 18 years and I count myself blessed to have worked in Westminster for almost a quarter of a century.

“Despite what some in the media have implied, I and my team of caseworkers have continued to work for my constituents faithfully and diligently to this day.”

Pressure has been increasing on Ms Dorries to formally resign from Parliament, with more than 3,500 people signing a public petition calling for a change in the law that would force a by-election.

The petition seeks to make MPs absent from their constituencies and Parliament subject to recall.

An MP can only be forced out if they break certain parliamentary rules. Constituents are unable to trigger a by-election themselves.

Letters asking for Ms Dorries to step aside were sent to her by Flitwick Town Council, Shefford Town Council and Independent Ampthill Central Bedfordshire councillors Mark Smith and Gary Summerfield, along with the Green Party’s Susan Clinch.

References were made to her “scant interest” in the constituency and her “aversion to attending local events”.

Ms Dorries won the Mid Bedfordshire seat with a majority of 24,664 in 2019. The former Secretary of State for Culture, Media and Sport launched a television talk show, Friday Night with Nadine, on Talk TV earlier this year.

At least seven candidates are expected to contest the constituency. Festus Akinbusoye is standing for the Conservatives, Dave Holland for Reform UK, Emma Holland-Lindsay for the Liberal Democrats, CBC chairman Gareth Mackey as an Independent candidate, Cade Sibley for the Green Party, Alistair Strathern for the Labour Party and Alan Victor for the True and Fair Party.