It is more than a year since Birmingham Liberal Democrat councillor Ayoub Khan was found by the Elections Commissioner to have mounted a “scurrilous and unwarranted attempt” to mislead an election court and to have made “unpleasant, unsupported and unsubstantiated” allegations about the conduct of his Labour opponent, Muhammed Afzal.

Put briefly, Timothy Straker QC castigated Coun Khan for attempting to wrongly implicate Coun Afzal in a witness intimidation plot and insinuate that supporters of Coun Afzal were responsible for an arson attack on a Range Rover owned by a Liberal Democrat supporter. There was, it turned out, not a shred of truth in either allegation.

What has happened to Coun Khan since then, you might ask?

The answer is that he has been protected by the Liberal Democrats, remains a cabinet member on Birmingham City Council and is his party’s prospective candidate for Ladywood at the next general election. The fact that Coun Khan continues to hold public office, and seeks even higher office, at a time when the probity of politicians is under scrutiny as never before is quite extraordinary. His defence until now has been that, since he was appealing against the Election Commissioner’s findings, it would be unfair to expect him to stand down from the council and resign as an election candidate. But Coun Khan’s attempt to clear his name finally failed on Friday when an application for a judicial review was rejected by the High Court.

The time is right now, as Labour are suggesting, for Liberal Democrat leader Nick Clegg to sack Ayoub Khan as Ladywood candidate. But this is not just a matter for the Lib Dems. Tory city council leader Mike Whitby must show his commitment to clean politics by removing Coun Khan from the cabinet immediately.