The UK’s ruling Conservative Party faces a tough by-election test after former MP Imran Ahmad Khan quit parliament on Thursday following his conviction for sexually assaulting a 15-year-old boy. Khan, 47, who represents the northern English city of Wakefield, said he would resign in order to “focus entirely on clearing my name”. “While legal proceedings are ongoing, I do not believe that it would ordinarily be appropriate to resign,” he wrote on Twitter.