Dominic Raab and Gavin Williamson could be casualties of a shake-up of parliamentary constituencies.
Under plans from the Boundary Commission revealed on Tuesday, the number of seats in England would increase from 533 to 543.
Although the total number if MPs will remain at 650, the aim is to ensure all seats broadly have a similar number of voters.
Williamson, who is being investigated over abusive messages to former chief whip Wendy Morton, could see his South Staffordshire constituency vanish altogether under the proposals.
The close ally of the prime minister has also been accused of telling a senior civil servant to “slit your throat” when he was defence secretary.
Williamson argued changes to his seat would disrupt the “unique character” of the constituency.
But the Boundary Commission decided his counter-proposal would actually “significantly disrupt local ties in parts of Birmingham and the Black Country”.
Raab, the deputy prime minister, is already facing a tough fight to hold onto Esher and Walton, where he has a majority of just 2,743.
Changes to the borders of the seat could make it easier for the Lib Dems to unseat Raab after the Commission rejected the Conservative Party’s objections.
Ed Davey, the Lib Dem leader, has made targeting the so-called Blue Wall of Tory-held seats in the south of England key to his electoral strategy.
The new boundaries will also mean Keir Starmer’s home in north London will no longer be in his Holborn and St Pancras seat.
Tim Bowden, the secretary to the Boundary Commission for England, said the new electoral map was the “culmination of months of analysis”.
“We now believe we are close to the best map of constituencies that can be achieved under the rules we are working to,” he said.
A third and final consultation on the new map of revised constituency proposals is open now until December 5.