An MP jailed for lying about a speeding offence has lost an appeal against her conviction.
Peterborough MP Fiona Onasanya was sentenced to three months in January for perverting the course of justice.
Sir Brian Leveson said at the Royal Courts of Justice there was “absolutely no basis” for the challenge.
Commons Speaker John Bercow has begun a recall petition process which could lead to Ms Onasanya’s removal as an MP, with a by-election held to replace her.
Ms Onasanya, 35, had claimed someone else was driving her car when it was seen speeding on 24 July 2017.
The MP’s Nissan Micra was clocked doing 41mph in a 30mph zone in Thorney, Cambridgeshire.
Representing herself, Ms Onasanya said: “The charge against me was perverting the course of justice. I said from the outset, and I still maintain my innocence, that I did not do that.”
Rejecting the appeal bid, Sir Brian said: “This applicant was tried fairly by a jury, who rejected her evidence on oath.
“There was no error of law in the approach of the judge, whose directions… were clear and accurate, nor was there any other irregularity with the trial.
“It is a tragedy that she has damaged, probably irreparably, a promising political career, but there is absolutely no basis for challenging her conviction.”
Addressing MPs in the House of Commons, Mr Bercow said the decision triggered the provision of the Recall of MPs Act 2015.
“I will accordingly be writing to the relevant petition officer to inform that person that Fiona Onasanya is therefore subject to a recall petition process,” he said.
This means a six-week petition will be open for Ms Onasanya’s constituents.
If 10% of them – about 7,000 people – sign the petition, a by-election will be held for the seat.
Ms Onasanya served less than four weeks at Bronzefield Prison in Surrey and was released on 26 February.
The day before, the attorney general’s office had concluded her sentence was not unduly lenient.
Jurors at the Old Bailey were told she colluded with her brother Festus, 34, who was jailed for 10 months after pleading guilty to perverting the course of justice.
Ms Onasanya stepped down as a party whip in November and was expelled from the Labour party following her conviction, when she became the first sitting MP for nearly three decades to be jailed.
But she did not give up her Peterborough seat, a move which would have triggered a by-election.
A Labour spokesman repeated the party’s call for her to “do the decent thing” and stand down.
“If she refuses to stand down, Labour will actively support local residents in their efforts to trigger a by-election through a recall petition,” he said.