Imran Ahmad Khan has announced he will resign as an MP after he was thrown out of the Conservative Party following his conviction this week for sexually assaulting a 15-year-old boy.
It means Boris Johnson faces a potentially difficult by-election in the Wakefield constituency - one of the so-called Red Wall seats the Tories snatched from Labour in 2019.
Khan was expelled from the Tories moments after a guilty verdict was returned against him on Monday over an historic offence in 2008.