She told GB News: “If we don’t get it right, and if we don’t stop the boats, the British people are not going to forgive us”.

MPs will vote on the legislation next week.

She said she will vote against the “fundamentally flawed” bill if the Prime Minister does not toughen it up, warning that other Tories might join her.

But the former Home Secretary told GB News that her criticisms are “not about bringing down the Government”.

She explained: “This is about delivering a bill that works and stopping the boats.

“I’m here because I believe vividly in things. I’m here because I believe passionately in delivering for the British people.

“They are fed up with the boats. They are fed up with broken promises.

“This is our last chance to get it right. And woe betide a government that fails the British people again.”

Braverman added: “What my objective is, is to deliver a bill that works. And it’s far better to defeat this bill, because it doesn’t work, and start again with a new bill that will work than proceed on a false premise, than proceed on a basis that amounts to something that won’t stop the boats.

“We may all feel a temporary sense of achievement by passing a bill but in a few months time when we see that plane grounded on the tarmac, when we’re failing to remove people to Rwanda, when we are clogged up in the courts – it will be very, very disappointing and people will ask us rightly, what did you do to try and avoid that catastrophe?

“That’s what I’m trying to do now. I’m trying to avoid a catastrophe of failing to deliver on this pledge.”

More than 30 Tory MPs are poised to back amendments to the bill when it returns to the Commons.

Sunak said earlier this week that he welcomed “bright ideas” which would ensure that his Rwanda plan works to break the business model of the cross-Channel people traffickers.

Amendments proposed by former Immigration Minister Robert Jenrick and Sir Bill Cash are seeking to toughen up the bill, with measures aimed at stopping judges on the European Court of Human Rights from frustrating ministers’ implementation of the Rwanda play.

Jenrick, who resigned as Immigration minister over weaknesses in the Government’s Rwanda bill, warned: “The stakes for the country could not be higher.”

ADDITIONAL REPORTING BY CHRISTOPHER HOPE