Two crunch by-elections will be held next month which could prove decisive for Boris Johnson.
Contests are due to take place in Wakefield, and Tiverton and Honiton to replace two Conservative MPs who resigned in disgrace.
Conservative chief whip Chris Heaton Harris moved the writ in the Commons, a formal process which begins the countdown to polling day.
The by-elections must be held within 21 to 27 days of the writ being moved, with the contests expected to be held on June 23.
Both ballots present different challenges for the Tories, who will be attempting to see off Labour in the Red Wall seat of Wakefield, while preventing a Liberal Democrat challenge in Tiverton and Honiton, in Devon.
Wakefield will also be a key target for Labour leader Keir Starmer, who must win back seats in the party's former heartlands in the North and the Midlands to get a shot at No10.
Here's what at stake in both contests.
Wakefield
All eyes will be on the vote to replaced disgraced MP Imran Ahmad Khan, who formally quit his Wakefield seat earlier this month after his conviction on 11 April for sexual assaulting a 15-year-old boy.
He is due to be sentenced later this month but has said he intends to appeal against his conviction.
Khan was only elected in 2019 when Boris Johnson won an 80-strong Commons majority by seizing swathes of the so-called Red Wall.
Wakefield had previously never returned a Tory MP in the post-war period.
A win here is critical for both Boris Johnson and Keir Starmer ahead of the next general election, which is expected to be held in 2024.
Tiverton and Honiton
Voters will also head to the polls in true-blue Tiverton and Honiton to elect a successor to porn Tory Neil Parish.
Mr Parish resigned last month after he admitted to watching X-rated videos on his phone in the Commons chamber.
The former farmer claimed he had been initially searching for tractors when he stumbled across the explicit material, which allies suggested may have been a brand of combine harvester known as a Dominator.
The Devon constituency has always elected Conservative MPs since it was created in 1997.
But the seat is a key example of Boris Johnson's other electoral headache - keeping his grip on the Conservatives southern heartlands.
The Liberal Democrats are gunning for the Tories in the south of England, emboldened by gains in the recent local elections.
This breaking story is being updated.
