Nadine Dorries could be forced out of parliament by MPs, after the former culture secretary rebuffed demands she honour he promise to quit.
The Lib Dems will table a “dosser Dorries” motion when parliament returns next month that would see Dorries suspended from the Commons for 10 days if she doesn’t show up by September 14.
Under existing rules, a suspension of that length would mean a by-election would be triggered in her Mid Bedfordshire seat if 10% of her constituents demand it.
Dorries dramatically announced in June she was resigning from parliament “immediately” after she was denied a seat in the House of Lords.
But the close ally of Boris Johnson has yet to formally stand down, despite not having spoken in the Commons chamber since June 7, 2022.
This week she insisted she was “working daily” on behalf of her constituents.
Dorries decision to remain in place has caused widespread frustration among Tory MPs who fear she is damaging the party, but there is currently no clear way to force her out.
Daisy Cooper, the Lib Dem deputy leader, said her party’s motion would be introduced on September 4.
“For months Nadine Dorries has treated the people of Mid Bedfordshire with contempt and taken them for granted,” she said.
“We need an end to this sorry saga, once and for all. Nadine Dorries must resign, if not then this government must do the right thing and force her to.
“Every day that Rishi Sunak sits on his hands the people across Mid Bedfordshire are being failed.”
Sunak has criticised Dorries, telling her that people in her seat “aren’t being properly represented”.
There is no love lost between the pair, with Dorries having accused the “posh” prime minister of blocking her peerage, something No.10 has strongly denied.
Dorries had expected to be given a seat in the Lords as part of Johnson’s resignation honours list. But her place was not approved by the independent body that vets applicants.
Two local councils in Dorries’ constituency have also demanded she stand aside.
Keir Starmer has said Dorries has “got to go” and trigger a by-election, which Labour would be hopeful of winning. “She hasn’t been representing them for a very long time,” the Labour leader told LBC.
“She said she would resign with immediate effect. I don’t know what her dictionary definition of immediate effect is. But ten weeks after the event doesn’t seem immediate.”