(Bloomberg) -- Britain’s governing Conservative Party might ordinarily have rejoiced at the resignation of Nicola Sturgeon. The Scottish leader has frequently clashed with London over Brexit, the handling of the pandemic and her demand for another independence referendum.

But with the Tories trailing badly in the polls, some in the party are concerned the departure of one of their most prominent foes gives the opposition Labour Party more of an opportunity to claw back some support in what used to be its Scottish heartland.

One Tory MP said that any weakening of Sturgeon’s Scottish National Party would benefit Labour at the next election, and therefore make it even harder for the Prime Minister Rishi Sunak to stay in power. 

The next election is due by January 2025, and Sturgeon’s shock decision to quit leaves her party and the Scottish independence movement in disarray at a critical juncture. Scotland’s figurehead since 2014, Sturgeon will cast a long shadow over a successor who will be tasked with uniting her party behind a strategy to win big in the UK vote.

The SNP plans to convene next month to decide how to pursue a referendum on leaving the UK after the Supreme Court ruled late last year that the Scottish Parliament didn’t have the right to call one unilaterally.

On the table is whether to frame the UK election in Scotland as a de facto plebiscite, Sturgeon’s original Plan B, or to instead use the 2026 Scottish Parliamentary election. Either way, polls show there’s a mountain to climb: the SNP has only once won a majority of the popular vote, in 2015.

So what comes next has ramifications beyond Scotland. Labour is leading the Conservatives by at least 20 percentage points nationwide. But a big enough victory isn’t guaranteed in Britain’s first-past-the-post system should that narrow. Any seats the party can take in Scotland, once a key pillar of support, would make the job more realistic.

Sturgeon Was the Tories’ Best Foil. Not Anymore: Therese Raphael 

Labour is cautious on its prospects, according to a person familiar with the party’s strategy. The departure of Sturgeon is positive for keeping the UK together and could give Labour a boost, they said. But the party needs to bounce back from being hollowed out years ago.

Scotland was dominated by Labour in the Westminster Parliament until the 2015 wipe-out, when it lost 40 seats and the SNP swept up 56 of 59 constituencies north of the border. Labour ended up with one. It managed to win six seats back in 2017 before losing them again two years later, and once again holds just one.

The SNP saw its support drop in at least one poll recently, along with backing for independence. That was after the UK government blocked legislation passed by the Scottish Parliament for the first time, rejecting a controversial gender recognition bill championed by Sturgeon.

Conservative MPs and strategists who spoke to Bloomberg said Sturgeon’s departure was a blow to the independence movement and a boost for the union. One adviser claimed Sunak’s decision to intervene to block the gender recognition legislation in January was a tactical victory that contributed to her downfall and helped protect the UK. 

However, some Tories cautioned that while in the medium-term the union may be more likely to survive, in the short term their own already bleak electoral prospects could be further damaged. Indeed, if anyone was to benefit it would be Labour leader Keir Starmer, they said.

Indeed, not having to contend with Sturgeon — one of the UK’s most popular politicians who galvanized opposition to Brexit and won kudos for her handling of the coronavirus pandemic – might come as some relief.

The question is whether Labour can capitalize enough at the ballot box, or whether the anti-independence vote in Scotland will continue to coalesce around the Conservatives who themselves have just six Scottish seats in Westminster.

--With assistance from Alastair Reed and Alex Morales.

©2023 Bloomberg L.P.