Suella Braverman has warned the Conservatives face “electoral oblivion in a matter of months” if they introduce emergency Rwanda legislation which is “destined to fail”.

The former home secretary delivered the warning in a personal statement to the Commons focused on what she called “mass, uncontrolled, illegal immigration” involving thousands of “mostly young men, many with values and social mores at odds with our own”.

Mrs Braverman, who was sacked from her Cabinet job last month, questioned if the Government understands the “unsustainable pressure” placed on public finances and services, and the impact on community cohesion and national security.

She said Prime Minister Rishi Sunak should be “commended for dedicating more time and toil than any of his predecessors to this endeavour” before outlining her expectations for emergency legislation to revive the Rwanda deportation scheme.

The legislation attempts to enable Parliament to deem Rwanda a safe destination and address the concerns that saw the Supreme Court rule Mr Sunak’s flagship asylum policy unlawful.

Mrs Braverman said: “On Monday, the Prime Minister announced measures that start to better reflect public frustration on legal migration. He can now follow that up with a Bill that reflects public fury on illegal migration and actually stops the boats.

“It is now or never. The Conservative Party faces electoral oblivion in a matter of months if we introduce yet another Bill destined to fail. Do we fight for sovereignty or do we let our party die?

“I may not have always found the right words in the past, but I refuse to sit by and allow us to fail. The trust that millions of people placed in us cannot be discarded as an inconvenient detail.

“If we summon the political courage to do what is truly necessary, difficult though it may be, to fight for the British people we will regain their trust. And, if the Prime Minister leads that fight, he has my total support.”

Earlier in her speech, Mrs Braverman outlined her “deeper concern” about the possible substance of the Bill after noting she previously voiced concerns over the Illegal Migration Act – at one stage suggesting the latter legislation should have been scrapped in favour of a “more robust alternative that excluded international and human rights laws”.

She said: “Previous attempts have failed because they did not address the root cause of the problem: expansive human rights laws flowing from the European Convention on Human Rights (ECHR), replicated in Labour’s Human Rights Act, are being interpreted elastically by courts domestic and foreign to literally prevent our Rwanda plan from getting off the ground.

“And this problem relates to so much more than just illegal arrivals. From my time as home secretary, I can say that the same human rights framework is producing insanities that the public would scarcely believe.

“Foreign terrorists we can’t deport – because of their human rights. Terrorists that we have to let back in – because of their human rights. Foreign rapists and paedophiles who should have been removed but are released back into the community only to reoffend – because of their human rights.”

Mrs Braverman added: “It is no secret that I support leaving the European Convention on Human Rights and replacing the Human Rights Act with a British Bill of Rights that protects the vulnerable and our national security, and finishes the job of Brexit by extricating us from a foreign court and restores real parliamentary supremacy.

“But I accept that the Government won’t do that and that it’s a debate for another day.

“Crucially, when it comes to stopping the boats now, leaving the ECHR is not the only way to cut the Gordian Knot.

“Emergency legislation would enable this if it meets the following tests.”

Mrs Braverman said the Bill must address the Supreme Court’s concerns about the safety of Rwanda and enable flights before the next election by “blocking off all routes of challenge”.

She said: “The powers to detain and remove must be exercisable notwithstanding the Human Rights Act, the European Convention on Human Rights, the Refugee Convention, and all other international law.”

Mrs Braverman said the Bill should enable removals to take place within days of people arriving legally and must enable the “administrative detention of illegal arrivals until they are removed”.

She said: “And, just as we rapidly built Nightingale hospitals to deal with Covid, so we must build Nightingale-style detention facilities to deliver the necessary capacity. Greece and Turkey have done so and the only way to do this, as I advocated for in Government, is with support from the Ministry of Defence.

“And fifth, Parliament must be prepared to sit over Christmas to get this Bill done.

“All of this comes down to a simple question: who governs Britain? Where does ultimate authority for the UK lie? Is it with the British people and their elected representatives or is it in the vague, shifting and unaccountable concept of ‘international law’?”