MPs arrested for serious sexual or violent offences could be banned from attending Parliament under new plans approved on Monday.
It comes despite the government putting forward a motion that recommended MPs are only barred if they are charged.
MPs voted 170 to 169 – a majority of one – for the threshold to be arrest instead.
A union representing workers in Parliament said the move was an “overdue victory for common sense”.
However, some MPs had raised concerns it was unconstitutional and would deny constituents the right to representation in Parliament on the basis of the decision of a committee.
Currently, if an MP is accused of sexual wrongdoing, parliamentary authorities have no power to ban them. There have been cases where MPs have stayed away voluntarily pending investigation.
A cross-party group of senior MPs worked on a plan to introduce new rules which initially proposed that a risk assessment would take place, determining whether an MP should be prevented from attending the parliamentary estate if they were arrested on suspicion of committing a violent or sexual offence.
Commons leader Penny Mordaunt instead tabled a plan focusing on those who had been charged – a much higher bar.
The government said the policy had been revised following feedback from MPs, to take into consideration the “detrimental impact that having no voice in Parliament can have on communities”.
The risk assessment would be carried out by a panel, appointed by the Commons Speaker, who would decide on appropriate measures, including exclusion from Parliament or from domestic or foreign travel funds.
Any decision would remain confidential, and an excluded MP could still apply for a proxy vote, meaning another MP could cast a vote in Parliament on their behalf.
