MPs have voted to suspend Peter Bone from the Commons for six weeks after an investigation found he had bullied and was sexually inappropriate around a former member of staff.
The move is likely to lead to a by-election in his Wellingborough constituency, a former Tory safe seat polling indicates could flip to Labour.
Parliament's behaviour watchdog found Mr Bone had exposed himself to an aide and physically struck him.
Mr Bone denies the charges.
The Conservative Party had already withdrawn the whip from the MP, meaning he will not be able to stand for re-election as a Tory candidate and he currently sits as an independent.
MPs voted in favour of suspending Mr Bone from parliament for six weeks.
The suspension had been recommended by Parliament's Independent Expert Panel (IEP) after it found Mr Bone broke sexual misconduct rules by indecently exposing himself to the staffer during an overseas trip.
Labour's shadow leader of the House of Commons, Lucy Powell called for Mr Bone to resign.
She said: "The people of Wellingborough deserve an MP they can be proud of. The country deserves the change that only Labour can bring."
Philip Hollobone, Tory MP for Kettering which neighbours Mr Bone's constituency, called the expulsion was "a very sad day" in parliament.
"Peter has been an outstanding MP for 18 years, he has helped tens of thousands of local residents with difficulties they've had - that it should come to an end like this I think it is very sad for all concerned," Mr Hollobone said.
Asked about the possibility of a petition of Wellingborough constituents garnering enough signatures to launch a by-election, Mr Hollobone said "Peter Bone has been incredibly popular MP for a very long period of time."
If an MP is suspended for over 10 days due to misconduct, a recall petition is started. A by-election happens if at least 10% of local voters sign the petition, according to the Recall of MPs Act.
The prospect of another by-election creates a potential headache for Prime Minister Rishi Sunak - who has seen his inherited majority eroded by a string of by-election defeats in recent months.
At the last general election Mr Bone won a majority of 18,540 - which is smaller than the Tory majorities overturned by Labour in October in both Tamworth and Mid Bedfordshire in 2019.
Mr Bone has held his seat for the Conservatives since 2005, growing his party's share of the vote.
In July 2022, then Prime Minister Boris Johnson appointed Mr Bone to the job of deputy Commons leader, which involves handling how complaints of bullying are dealt with. He was sacked from the role by Mr Johnson's successor Liz Truss.
Mr Bone's former assistant told the BBC the experience led to him being diagnosed with post-traumatic stress disorder.
The ex-staffer said Mr Bone's "physical, emotional and psychological abuse" left him a "broken shell of the young man I once was".
The Conservative Party launched an investigation into Mr Bone's conduct in 2018, but the party says "the complainant withdrew from the process before the case was heard".
The IEP upheld five complaints against Mr Bone sexual misconduct rules by indecently exposing himself to the staffer during an overseas trip.
The investigation was based on a complaint made to the body by a former member of staff, over alleged behavior which took place more than 10 years ago.
Mr Bone appealed against the investigation's findings, arguing it had been flawed. However, his appeal was dismissed.
The watchdog recommended Mr Bone should be suspended from the House of Commons for six weeks. Photo by David Woolfall, Wikimedia commons.