Lars Ohly led the Left Party 2004-2012, and has continued to have a prominant position in the public debate, lately as the chairman of an organisation for people with disabilities.
Last autumn, a woman accused Ohly of sexually harassing her during a evening event for party faithfuls in October. Ohly has denied the accusation but has apologised for what he himself says was a "too pushy and persistant" towards the woman.
The incident was reported to the police, which did not pursue the case further.
On Tuesday, Ohly announced that he is leaving the party, because of how the party leadership has treated him since the accusations emerged. He said no investigation has been carried out, no-one had asked him for his version of events, but instead they have banned him from taking part in all party activities in a way that he says is against the party's own rules.
In a written comment, the Left Party's deputy chairperson, Hanna Gedin, said that "it is regrettable that Lars Ohly chooses to leave the Left Party. This is nothing that we have demanded or wanted. Lars Ohly has been an important person in our party and I regret that he has not wanted to meet our wish to safeguard the affected woman, by avoiding party arrangements for a period".