Van Doorn is a bizarre figure. Once part of Geert Wilders’ Freedom Party, the party broke with Van Doorn in December 2011. In April 2012, Van Doorn announced his conversion to Islam. He expressed regret that he had been involved in making Wilders’ short film Fitna. Van Doorn became head of the European Da’wa Foundation.

He has been accused of antisemitic remarks, including one about a Jewish Canadian who paid a ransom to free Yazidi and Christian hostages, and about whom he tweeted “To sell at a profit?” Called out on it, Van Doorn claimed he had only been joking.

Van Doorn has also described the failed coup in Turkey as the work of “Zionists.” On May 4, National Memorial Day in the Netherlands, when the more than 100,000 Dutch Jews murdered in the Holocaust were remembered, Van Doorn said that Palestinians were equal to the victims of the Holocaust. He has also tweeted “May Allah exterminate the Zionists.”

Dutch police have arrested a politician in the Hague on suspicion of involvement in a plot to assassinate Prime Minister Mark Rutte.

The prime minister’s security service said Arnoud van Doorn, the leader of The Hague Unity Party, was arrested on Sunday.

He “displayed suspicious behaviour” as he walked through the same area of the city as Mr Rutte, the service said.

Mr van Doorn was released on Monday after a police interrogation.