Rishi Sunak and Liz Truss will face off to become next Prime Minister

Rishi Sunak and Liz Truss will face off to become Britain's next Prime Minister, after Tory MPs finished whittling down candidates from eight to two.

Penny Mordaunt, who surprised many early in the Tory leadership race, fell at the final hurdle and failed to secure enough backers to make her pitch to the Conservative Party membership this summer.

Ahead of this afternoon's ballot, which saw Mr Sunak receive 137 votes and Ms Truss 113, there were widespread allegations of "dirty tricks", with claims the former chancellor’s supporters had been encouraged to vote tactically to ensure a run-off with Ms Truss rather than Ms Mordaunt.

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Former Cabinet minister David Davis, who backed Ms Mordaunt, said “he wanted to fight Liz, because she’s the person who will lose the debate with him”, adding that it was the “dirtiest campaign I’ve ever seen”.

Ms Truss, who is being backed by Boris Johnson’s most loyal allies, insisted that she was the “only person who can deliver the change” the UK needs which is in “line with true Conservative principles”.

While Mr Sunak pledged to unite and "bring people together to serve the British people to the best of our ability”.

But he refused to say whether his Cabinet would include Ms Truss and Ms Mordaunt.

“I’ve been particularly careful as I assume the others have been as well, not to get into the business of starting to talk about specific jobs and specific people,” he said.

On tax, the issue that has dominated the race to replace Mr Johnson, Ms Truss, whose tax-cutting promises have been criticised by former Cabinet minister David Davis as having “gone a bit far”, insisted they were “affordable”.

She said: