A by-election in Peterborough to find a replacement for Independent MP Fiona Onasanya is to be held on June 6.
Labour moved the writ for the poll in the House of Commons a day after the 35-year-old solicitor became the first MP to lose her seat through a recall petition.
More than a quarter of Peterborough’s registered voters signed a petition to remove Ms Onasanya after her conviction for perverting the course of justice by lying about a speeding offence.
It remains unclear whether she will stand in the by-election, as she is permitted to do under recall rules introduced by David Cameron in 2015.
Former MP and radio talkshow host George Galloway is among those who have already thrown their hats into the ring.
Mr Galloway, who sensationally won Bradford West from Labour in a 2012 by-election, said he would be the best-placed candidate to secure the full implementation of Brexit and “the one who’d make the biggest impact in the House”.
Nigel Farage’s Brexit Party confirmed it will contest the by-election, but had made no decision on whether Mr Farage would be the candidate.
Ms Onasanya won Peterborough for Labour by a wafer-thin majority of 607 in 2017. She was expelled from the party following her conviction, but stayed in Parliament as an Independent until she was removed by the petition.
The Cambridgeshire city is a classic Conservative/Labour marginal, changing hands between the parties as their national fortunes have ebbed and flowed over recent decades.
But with a 61% Leave vote in the 2016 EU referendum, Brexit will be a wild card on June 6, making the result virtually impossible to predict.
Conservative candidate Paul Bristow has promised to help deliver EU withdrawal, but is likely to face voter anger over Theresa May’s failure to deliver Brexit by the promised date of March 29.
The vote will take place a fortnight after European Parliament elections on May 23, in which Tories are lagging a distant third in polls, behind Labour and the Brexit Party.
Labour’s candidate is Lisa Forbes.