'Prominent politician' might be a bit of a stretch. The Green Party only have 1 MP in the House of Commons, they're hardly influential.

Also worth noting that he was suspended from the Green Party, subsequently joined the Liberal Democrats but was again suspended after his partner's tweets:

Knight was consequently suspended from the party on a no-fault basis, and the party launched an inquest into possible safeguarding failures as David was allowed to act as Aimee's election agent after having been charged.[26] In September 2018, Knight resigned from the Green Party citing transphobia[27] however Knight continued to cooperate with the inquest. The inquest by Verita found in January 2019 that she had committed a "serious error of judgement" in appointing her father as her campaign manager.[28][29] The report also said that the Green Party, who were told by Knight that her father had been arrested but not that he was a party member, could have done more to investigate the matter.[30]

In October 2018, she joined the Liberal Democrats, becoming the Diversity Officer of her local party.[31][32][33] She was suspended from the Liberal Democrats in July 2019, after tweets appeared on her partner's account admitting to having sexual fantasies involving sex with children. Knight said that her partner's account had been hacked.[34][2]

Also worth noting that he has a slew of mental illnesses, including autism and oppositional defiant disorder which, and I'm no psychiatrist, sounds like medicalising being a little turd.