A left-wing politician in Sweden has revealed he was raped at knifepoint by a man who told him he was a “traitor”.

Patrik Liljeglöd, group leader of the Left Party in the town of Falun, described what happened on Facebook and also at a meeting of the local council, despite his preference that “nobody else other than me would ever know”.

He said he felt he had to speak out because the attack was politically motivated and was therefore an attack on democracy.

Sweden’s Culture and Democracy Minister, Alice Bah Kuhnke, recently told The Local newspaper that she had asked police to crack down on crimes against free speech, particularly attempts to menace politicians, journalists and artists.

In 2014, 28 per cent of elected politicians reported experiencing violence, threats or harassment.

In the Facebook post, Mr Liljeglöd said he had an “important” message to convey about what had happened to him on a “gentle summer night” in July when he was walking home alone.

"I was brutally treated and also raped at knifepoint because [in his attacker’s words] I was a left-wing [expletive], that people like us like this, and finally that I was a traitor," he wrote.

"The few words expressed by the man had a clear connection to me as a politically active [person] and therefore it affects us all.

“Telling you what happened to me is not something I enjoy doing. I would rather bury this incident so deep down in the bedrock that nobody else other than me would ever know. Nor do I seek your compassion or empathy.

“I’m standing here because, given my deeply rooted conviction that democracy should be an inviolable part of our society, I feel that I have to.

“Nothing is more important than democracy. People die for the right to democracy every day and the right we have inherited through our parents' struggles, we must continue to fight for. And [regarding] the citizens who have forgotten why, we must remind them.”

Police said they were investigating the case.

"We have examined the crime scene and sent the results to the National Forensic Centre, but we are still waiting for their analysis," a police spokesperson told the TT news agency.