Lobbyist Frans van Drimmelen has quit coalition party D66 and resigned as a political consultant after he was accused of sexually harassing a party colleague.

Van Drimmelen said in a statement that he had had an extramarital affair in 2015 and made persistent attempts to contact the woman after it ended. But he disputed that he had abused his position in the party or that he was guilty of sexual intimidation,

More than 700 D66 members have called on party leader Sigrid Kaag to state what she knew about a private inquiry into Van Drimmelen’s behaviour, which concluded he had ‘stalked, threatened and blackmailed’ the woman between 2015 and 2016. He was given a formal warning by police but not charged.

The party members have also urged Kaag to publish an anonymised version of the report into Van Drimmelen’s behaviour, which was carried out by independent research agency BING following an anonymous blogpost by the woman in December 2020. Kaag is facing questions about why the report, completed in March 2021, had been kept quiet for a year

The party leadership has said it will present its conclusions on the matter on Friday. The public part of the investigation, focusing on whether there was a broader culture of sexual intimidation in D66, found there was ‘no question of an institutionally unsafe environment.’

The episode has damaged trust in Kaag and D66, with 78% of its supporters telling EenVandaag that they thought it cast the party in a bad light. Only 45% said they backed Kaag as leader, down from 71% a month ago.

In a statement to the AD and Parool newspapers, Van Drimmelen described the relationship, which he said ended in the summer of 2015, was a ‘stupid thing’.

‘Afterwards I tried to start a conversation by sending messages via various channels. I was keen to know why the affair had ended,’ he said.

‘The second stupid thing is that I tried for too long, too persistently and at times extremely unpleasantly to make that conversation happen. In doing so I sometimes said things that I realise came across as threatening. Even though it was made clear that the woman did not want any contact whatsoever.’

Van Drimmelen also stepped down from his position as partner in corporate communications agency Dröge and Van Drimmelen. ‘I am completely leaving public life and will work on a new future later,’ he said.