(Bloomberg) -- Rishi Sunak’s strategy to rouse his despondent Conservative lawmakers after disastrous local election results unraveled in dramatic fashion on Wednesday as — moments before he stood up to speak in Parliament — one of them defected to the poll-leading opposition Labour Party.

The move by Natalie Elphicke, who represents the Dover and Deal constituency in southeast England, was timed to cause maximum damage. Prime Minister’s Questions is a chance for sound bites and point-scoring, and Sunak is following up this week’s by inviting Tory MPs into Downing Street for a campaign presentation ahead of a UK vote expected in the autumn.

Sunak’s team planned the event as part of a fight back after the Tories lost a parliamentary district, hundreds of local council seats and high-profile mayoralties in England last week. Though he is likely safe from any attempts to replace him, the premier still needs to keep his lawmakers motivated if he is to avoid a whitewash in a general election he must call by the end of January.

But the scenes in Parliament and Elphicke’s defection point to how difficult that will be. She is a controversial MP, yet her constituency on the southern coast is on the front line of one of Sunak’s five key promises: to stop migrants arriving in small boats across the English Channel.

“He’s not stopping the boats and he’s letting this country down,” Elphicke told Sky News. She also took aim at the Tory record on housebuilding, another key area for the election. “In 2019, the Conservatives stood on a manifesto that was very much center ground, but under Rishi Sunak they’ve abandoned the center ground and broken many election promises.”

Sunak’s office hit back immediately. The prime minister’s press secretary used a regular briefing with reporters to highlight Elphicke’s past criticism of Labour, including on immigration.

Yet it was clear in the Commons that Elphicke’s defection came as a shock, and the risk for Sunak is that it further fuels the sense that he’s losing the confidence of his backbenchers. The latest switch comes hot on the heels of another Tory MP, Dan Poulter, defecting to Labour. Lee Anderson, who Sunak made deputy party chairman, defected to the Reform UK party this year. 

The Tories are also shedding MPs at the ballot box. Even before Labour took Blackpool South last week, the Conservative administration had accrued more by-election defeats in a single term than any government since the 1960s. 

In the House of Commons, Labour Leader Keir Starmer gestured to Elphicke sitting on his party’s benches, jibing Sunak about “losing two MPs in two weeks” — a reference to Poulter. 

To be sure, welcoming Elphicke is also a political risk for Starmer. Three Labour lawmakers told Bloomberg they were unhappy with the decision to accept her into the party. They cited her controversial support for her husband Charlie Elphicke, a former Tory MP who was convicted of sexual assault in 2020.

She has previously accused Labour of trying to create loopholes for asylum-seekers and triggered a backlash when she criticized footballer Marcus Rashford over his campaign to push the government to provide free school meals. Her views are not an obvious fit for Labour, especially on the left of the party.

“It certainly is a stunt that damages the Tories,” John McDonnell, who was Labour’s shadow chancellor under former leader Jeremy Corbyn, told LBC Radio’s Tonight with Andrew Marr. “But it also has implications for the Labour Party as well, because of the views that Natalie Elphicke has expressed in the past, and some of which I don’t think the party should be associated with.”

A major part of Starmer’s calculation appears to be that Elphicke — just like Poulter — will stand down at the general election, meaning she won’t be a candidate for Labour. He is also likely to see a high-profile former Tory MP willing to criticize Sunak — especially on areas like migration, where the Conservatives will try to attack Starmer — as worth the gamble.

“What is the point of this failed government staggering on,” Starmer asked Sunak, when “the Tory MP for Dover on the front line of small boats crisis says the prime minister cannot be trusted with our borders, and joins Labour?”

--With assistance from Ellen Milligan, Alex Wickham and Isabella Ward.

(Updates with more Labour reaction three paragraphs from bottom.)

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