LIZ Truss vowed to enforce the controversial Rwanda policy last night as the battleground in the Tory leadership race centred on immigration.
It came as a poll of general voters showed they believed ex-Chancellor Mr Sunak would make a better Prime Minister than Ms Truss.
Some 43 per cent believe Mr Sunak would be a good PM compared with 36 per cent for front-runner Ms Truss, according to Opinium.
But in a Tory membership poll, Mr Sunak has only 38 per cent support while his rival has 62 per cent.
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Ms Truss has pledged to stick with the Rwanda policy — where migrants who cross the Channel in small boats are sent to the East African country — and strike further similar deals with other countries.
And Ms Truss last night said she would boost the number of officials at the border by a fifth to 10,800 if she gets the top job in September.
She said: “The Rwanda policy is the right policy.
“I’m determined to see it through to full implementation, as well as exploring other countries we can work with on similar partnerships.
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“I’m also determined to make sure we have the right level of forces at our border.”
She has also said she will introduce a beefed-up Bill of Rights to address illegal immigration, a policy she sees as an “absolute priority”.
She said: “We need to make sure that the British Bill of Rights fully delivers on giving the UK government the powers — and UK parliament the sovereignty — to be able to deliver the policy in full.”
She said countries have been identified where other deals could be struck.
The deal with Rwanda has already cost taxpayers £120million upfront.
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A judicial review on the legality of the policy is set to start on September 5, the day the winner of the Tory contest is announced.
Mr Sunak has pledged to create an annual cap on the number of refugees accepted each year through safe and legal routes.