Embattled minister Sir Gavin Williamson has failed in his bid to prevent his constituency being carved up, which could see him struggle for reselection ahead of the next general election.

The Boundary Commission for England has rejected his argument not to merge his South Staffordshire constituency with a section of another as the number of MPs in the region shrinks.

Another loser from the shake-up looks to be Dominic Raab, with the Liberal Democrats believing the changes will increase their odds at snatching the Surrey seat of the Deputy Prime Minister and Justice Secretary.

How the UK electoral map could change
(PA Graphics)

The commission’s revised proposals published on Tuesday sees the number of constituencies in England increasing from 533 to 543.

But the county of Staffordshire in the West Midlands would go from 12 to 11 MPs, and with all seats currently held by Conservatives, someone in the area would lose out.

Sir Gavin’s seat is set to merge with part of South Dudley, currently held by Tory MP Mike Wood, to become Kingswinford and South Staffordshire.

The changes could see Cabinet Office minister Sir Gavin fighting Conservative colleagues for a seat to contest, potentially with Sir Bill Cash in the neighbouring seat of Stone.

Sir Gavin had argued that the “unique character” of Staffordshire would be negatively impacted by combining it with parts of the Black Country.

But the commissioners said his counter-proposals would see nine electoral wards split between constituencies, an increase of six from the initial proposals.

“They also concluded that the counterproposal would significantly disrupt local ties in parts of Birmingham and the Black Country, demonstrating the clear knock-on effects of treating Staffordshire as a standalone sub-region,” the report added.

They also judged that the proposals would cause “severe disruption to existing constituency boundaries and local ties across the region”.

“For this reason, they did not recommend changing the sub-region grouping for these revised proposals,” the report says.

The decision comes as Rishi Sunak defied calls to sack Sir Gavin despite conceding his threatening and abusive texts to a colleague are “not acceptable”.

Meanwhile, Mr Raab’s seat in Esher and Walton, where he commands a slim and shrinking majority over the Lib Dems, also faces changes, with analysts expecting them to benefit his rivals.

In 2019, the Lib Dems saw a surge of support to bring them within 3,000 votes of dethroning Mr Raab, and their internal projections put them on course for seizing the seat.

Privately, figures in the party agreed they would be further benefited by the proposed boundary changes removing two strongly Conservative-leaning wards.

A Liberal Democrat spokesman said: “We’ve been making great progress in this seat and are confident we can take the fight to the Conservatives there whatever the boundaries.”

The commission’s shake-up is aiming to ensure seats broadly have a similar number of voters, by redrawing boundary lines as people move around the nation.

Unless it is an “utter wipeout” for the Tories at the next election, Conservative peer and elections expert Lord Hayward said the party are the main beneficiary of the changes.

“Broadly the Tories will gain five to 10 seats net because the new seats are in overwhelmingly Tory areas,” he said.

The commission’s third and final consultation on a new electoral map is now open until December 5, with the final recommendations expected to be submitted to Parliament in July.