An investigation into the abuse of parliamentary candidates is being launched after a wave of intimidation during the general election campaign.
Labour and the Conservatives have both accused the other of failing to act to stamp out abuse by their members and activists after reports of racism, anti-Semitism and sexism.
Theresa May asked the Committee on Standards in Public Life to conduct a review into the problem as MPs gathered in Westminster Hall to discuss the apparent rise in personal attacks.
The probe will assess the current protections in place and report back to the Prime Minister with recommendations on ways to tackle abuse in the future.
Mrs May said: “I have been horrified by stories from colleagues about the scale and nature of the intimidation, bullying and harassment they suffered during the general election campaign.
“Robust debate is a vital part of our democracy, but there can be no place for the shocking threats and abuse we have seen in recent months.
“We must all work together to banish this behaviour, and I would urge MPs and candidates from all parties to report their experiences to this review so we get the fullest possible picture – and can take the action required to stamp it out.”
It comes after a cross-party group said political parties must do more to prepare candidates for the ruthless nature of campaigning.
The informal all-party parliamentary inquiry into electoral conduct found racism and bigotry have been “on the rise” at times since the 2015 general election.
It highlighted a number of cases of abuse during the latest campaign, including reports by Tory former minister Andrew Percy, a convert to Judaism, that he had been called “Zionist scum”.
Tory Sheryll Murray has told how she was left “sickened” when her posters were daubed with swastikas, while Ameet Jogia, an Indian-origin Conservative Party candidate who stood against Labour’s Barry Gardiner in Brent North, reported finding a voting booth vandalised with graffiti, stating: “Vote Labour Barry, not Jogia. Keep p**** out of politics”.
Labour accused the Conservative party of carrying out vitriolic personal attacks on election candidates on an industrial scale during the election.
Tories ran a nasty campaign full of smears and untruths about opponents, particularly shadow home secretary Diane Abbott, according to the Opposition.
Millions of pounds were spent on attack adverts on social media in a campaign that could deter future parliamentary hopefuls from entering politics, Labour said.