Rishi Sunak will face two crunch by-elections on the same day this summer, amid his ongoing bitter public row with Boris Johnson.
The government has decided to hold the contests to replace Johnson in Uxbridge and South Ruislip and his ally Nigel Adams in Selby and Ainsty on July 20.
It comes after the privileges committee report into whether Johnson lied about partygate found he had deliberately misled parliament on multiple occasions.
A third by-election is also looming, as Mid Bedfordshire MP Nadine Dorries has also announced she will quit parliament.
But the former culture secretary has yet to formally resign, scuppering Sunak’s hopes of limiting the political fallout by holding all three contests on the same day.
Labour is expected to overturn the Conservative’s 7,210 majority in Uxbridge and South Ruislip.
In Selby and Ainsty the Tories have a 20,137 majority over Labour, but the Conservatives have seen bigger majorities evaporate at recent by-elections.
Johnson dramatically quit as an MP on Friday ahead of the announcement he had been found guilty of lying to parliament over partygate.
Adams and Dorries announced they were walking away after not being handed peerages as they had expected.
When Dorries does eventually officially step down, the Lib Dems will hope to continue their run of big by-election wins by wiping out her 24,664 majority.
Sunak has suggested Johnson wanted him to ignore the recommendations of the independent House of Lords Appointments Commission and ensure Dorries and Adams were given seats in the Lords.
Johnson said the prime minister was talking “rubbish” and his camp accused Sunak of having “secretly blocked” the peerages for his friends.
Keir Starmer said the by-elections were effectively “political tantrums” caused by Johnson and his allies.