Former Conservative minister Nadine Dorries has announced she is resigning, after months of criticism over her absence from the House of Commons.
In her resignation letter, the Tory MP accused Rishi Sunak of “demeaning his office by opening the gates to whip up a public frenzy” against her.
The letter to the prime minister said: “It has 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 and you yourself have implied, my team of caseworkers and I have continued to work for my constituents faithfully and diligently to this day.”
The letter went on to say Mr Sunak had abandoned “the fundamental principles of Conservatism” and “history will not judge you kindly”.
Ms Dorries, a key ally of Boris Johnson, said she was resigning with “immediate effect” on 9 June after she failed to get a peerage in Mr Johnson’s resignation honours list.
But having not formally vacated her seat, a by-election has not been able to take place.
Ms Dorries said she was delaying her exit to investigate why she was refused a seat in the House of Lords, but many of her local Conservatives, constituents and fellow MPs accused her of “abandonning” the people of Mid Bedfordshire.
Both Flitwick and Shefford Town Council formally called for her to resign.
Following the letter, a Conservative Party spokesman said the party has already “selected a candidate and are ready for the by-election campaign”.
In it, Ms Dorries also accused Mr Sunak of leading attacks on her resulting in “the police having to visit my home and contact me on a number of occasions due to threats to my person”.
“The clearly orchestrated and almost daily personal attacks demonstrates the pitifully low level your government has descended to,” she wrote.
Attacking the prime minster’s record, she added: “Since you took office a year ago, the country is run by a zombie parliament where nothing meaningful has happened.
“You have no mandate from the people and the government is adrift. You have squandered the goodwill of the nation, for what?
“Your actions have left some 200 or more of my MP colleagues to face an electoral tsunami and the loss of their livelihoods, because in your impatience to become prime minister you put your personal ambition above the stability of the country and our economy.
“Bewildered, we look in vain for the grand political vision for the people of this great country to hold on to, that would make all this disruption and subsequent inertia worthwhile, and we find absolutely nothing.”