An MP has revealed she received death threats and was sent an image of a severed head around the time her colleague Jo Cox was murdered.
Rachael Maskell told the BBC the abuse came via social media and in some "very nasty emails".
The Labour MP for York Central said more needed to be done to tackle online abuse and protect young people.
She added that she was determined not to let the threats prevent her serving her constituents.
'Freedom of speech'
Jo Cox was shot and stabbed to death in Birstall, West Yorkshire on 16 June, 2016. The 41-year-old's killer, Thomas Mair, 53, was jailed for life in November after being found guilty.
Ms Maskell said despite being concerned for her safety and that of her staff, the death of Ms Cox was "so heavy" on her mind it "overrode everything else".
"I was just really raw after Jo's murder, and really concerned about her family," she said.
Ms Maskell said she had now chosen to talk about the threats she received in a bid to highlight the issue of online abuse and, particularly, how it affects young people.
She said: "Freedom of speech is so important - it is what we value across our country - but the abuse I received online went way beyond that.
"We need to make sure we have a zero tolerance to abusive behaviour online."
The MP is calling for social media firms to remove abusive posts and do more to trace those responsible.
It comes after shadow home secretary Diane Abbott said women may be deterred from entering politics because of abuse suffered by female MPs.
In February, John Nimmo, from South Shields, was jailed after he made anti-Semitic death threats to another female Labour MP and threatened to blow up a mosque.