Two bands who have called for members of the Conservative Party to be killed are to perform at Glastonbury Festival 2019.
One of Killdren’s best known songs is called Kill Tory Scum while Fat White Family have called for violence against Conservatives on social media.
The Jo Cox Foundation said the language was “completely abhorrent”.
“We’re seeing a legitimising and normalising of harmful words and actions,” it said.
Killdren, who are a “two-bit rave punk band” and claim to form the “ideal soundtrack to the worst generation in history”, will play at Glastonbury’s Shangri-Hell International TV stage on Friday 28 June.
Their lyrics include: “Even if it’s your dad or your mum, kill Tory scum, kill Tory scum…murder them all to the beat of a drum, kill Tory scum, kill Tory scum.”
The band also played a graphic set at Boomtown Fair 2018, in which they kicked, punched, and spat at a man dressed in a suit, while wearing Kill Tory Scum clothing.
The Glastonbury story was first reported by the Sunday Times. When asked about the song, the band told the paper: “The piece would not exist if the destructive and violent policies of the Tory party hadn’t taken such a devastating toll on the UK.”
The band’s YouTube page claims the song is “satirical discourse”.
Also due to perform at festival is Fat White Family, who previously played at Glastonbury’s Park stage in 2015.
Its song topics include abusive relationships, serial killers and addiction to class A drugs.
In a 2015 tweet, the punk rock band, from south-east London, said anyone who voted Tory had “blood” on their hands, and called for them to be executed.
A year earlier, they said Tories should be hanged.
Catherine Anderson, chief executive of the Jo Cox Foundation, said the language was “completely abhorrent”.
Jo Cox MP was killed by a right-wing extremist in 2016, days before the Brexit referendum.
Ms Anderson told the BBC: “The direct incitement of violence and abuse, on any platform and in any sector, is wrong and something that we absolutely reject.
“We’re seeing a legitimising and normalising of harmful words and actions, and this is leading to a decay in our shared language and ultimately our values, and that concerns us very much.
“We cannot but think of what happened to Jo, after whose murder we believed things would improve; instead, things have got a lot worse.”
The BBC has contacted Glastonbury for its response.