British politics is at a “dangerous moment” with the level of personal abuse aimed at election candidates having reached a “tipping point”, the head of the standards watchdog says.
Lord Bew warned the level of vitriol was now such that it could deter people from running for office.
Labour MP Diane Abbott said this week she had endured a torrent of “mindless” racist and sexist abuse.
MPs have blamed hard-left and far-right groups and the rise of social media.
During a parliamentary debate on Wednesday, MPs from all parties spoke about the harassment they and their staff had received both in person and online, including death threats, rape threats and anti-Semitic abuse.
Conservative MP Simon Hart said he had heard of candidates having swastikas painted on their offices, and that the “hashtag Tory scum had become a regular feature of our lives” on social media.
First-time candidate Emily Owen, who stood for Labour in Aberconwy in this year’s general election, has also spoken out about the sexually explicit messages she received online.
“I started having messages come through and they quickly became very explicit, with people explaining what they wanted to do to me – with or without my consent – asking lots of questions, what I would do to get votes,” the 22-year-old told BBC Breakfast.
Using strong and graphic language, Ms Abbott gave the debate examples of the offensive messages she and her staff had to endure every day, not just at election time, including people tweeting she should be hung.
Theresa May has asked Lord Bew, who chairs the Committee on Standards in Public Life, to look into what went on during the election campaign and whether existing laws need to be strengthened to protect candidates in future.
In an interview with BBC Radio 4’s Westminster Hour, Lord Bew said there was a problem in public life that had not been seen before.
“We are in a bad moment and we have to respond to it,” he said. “We cannot afford to lose people of quality in our public life and we may be approaching a tipping point.”
Conservative MPs say Jeremy Corbyn has been too slow to condemn the actions of left-wing activists, including members of the Momentum pressure group, who they claim have been targeting them as well some Labour MPs. Momentum has denied any involvement whatsoever.
Lord Bew said it was “absolutely clear” that the Labour leadership believed there was no place for threats or fear in politics but that political leaders, as a whole, needed to be more outspoken on the issue.
“Above all, we do need leadership from Parliament itself on this point. We have reached a point where this is not a sermon. This has got to be said with some sharpness.”
The committee, he added, was “in listening mode” and would not rule out anything at this stage.
“It’s perfectly obvious that the ways in which the culture of civility in this country has been eroded has come from a number of different sources.
“And we need to see if we can find ways of getting a tone in our public debate which is still vigorous but avoids that tinge of nastiness and hatred which has definitely entered into things in more recent times.”