Labour has been accused of granting an “amnesty” to tens of thousands of asylum seekers after scrapping the Rwanda programme.
James Cleverly reacted as Yvette Cooper, his successor as Home Secretary, announced that the deterrent measure had been scrapped.
Ms Cooper told MPs she would reverse part of former prime minister Rishi Sunak’s illegal immigration law.
The law bars anyone arriving in the UK illegally since March 2023 from being granted asylum, with those people set to be deported to the east African country.
The Refugee Council estimates that between 60,000 and 90,000 people will be granted asylum despite entering the country illegally.
In an article published in the Daily Express, Mr Cleverly warned that Britain was “heading blindly towards a small boat crossing nightmare this summer”.
The crisis has already worsened since Labour came to power, Mr Cleverly says, with official figures showing that nearly 1,500 migrants arrived in the UK on small boats crossing the Channel last week.
“The Labour Party has started the long march back to the European Union, with an immigration deal as the first thing on the table,” he warns.
“The last thing hard-working Britons need is more migrants.”
Labour’s approach to illegal immigration was ridiculed as a “cat and mouse game” in the Commons on Monday, while Ms Cooper was urged to show “courage” in tackling the problem.
But the Home Secretary told MPs the Rwanda project was an “expensive scam” that had cost British taxpayers £700 million, with just four volunteers sent there in total.
She accused the previous Conservative government of creating a “California asylum hotel”, where people entered the system but never left.
In a statement to MPs, Ms Cooper said the Conservatives had planned to spend more than £10 billion over six years on the Migration and Economic Development Partnership (MEDP).
She also warned that high numbers of small boat trips across the Channel were likely to persist into the summer, blaming weak border controls, which she said Labour had “inherited” from the previous administration.
“Two and a half years after the previous government launched it, I can report [the MEDP] “It has already cost the British taxpayer £700 million to send just four volunteers,” Ms Cooper said.
“During the six years of the [MEDP] The previous government had planned to spend over £10 billion of taxpayers’ money on this project. It did not inform Parliament of this.
These costs include £290m paid to Rwanda, “chartering flights that never took off” and “detaining and then releasing hundreds of people”, she said.
Ms Cooper warned that cooperation with European police forces was “too limited” and that more needed to be done to tackle people trafficking “upstream”, well before boats reach French shores.
Mr Cleverly accused her of using “made-up figures” and criticised the UK government for already making the problem worse.
He told MPs: “The reality is that everyone knows, including the people smugglers, that the small boat problem is going to get worse, and it has gotten worse under the Labour government because there is no deterrent.”
He added: “The fact that there is now no safe third country to return people who cannot be sent home means that we are asking ourselves: where are we going to send people who come from countries like Afghanistan or Iraq, in Syria?
“Has she started negotiations on return agreements with the Taliban, the Iranian ayatollahs or Assad in Syria? And if she is not going to send to Rwanda those who arrived here on small boats, to which local authorities will she send them?”
“We were closing hotels when I was in government and I wonder which local authorities will receive these asylum seekers if not Rwanda, will it be Rochdale, Romford or Richmond?”
Speaking in the House of Commons, Reform UK deputy leader Richard Tice warned: “If you crush one gang, it’s like playing whack-a-mole: another one will appear.”
He added: “Here is the question: how much time are you going to devote to your policy, Minister of the Interior, before you carry out the only policy [that] “Will this work, this is the policy that you actually started last week, which is to pick up and bring back to France, which is what we are entitled to do under international maritime law?”
Lee Anderson, a British Reform MP, urged Ms Cooper to “develop a political backbone and order the Border Force to turn the boats back the same day”.
Home Office figures show that nearly 1,500 migrants arrived in the UK on small boats crossing the Channel in one week.
Some 1,499 people made the crossing aboard 27 boats from July 15 to 21, while the French coastguard confirmed that two people died during rescue operations off the northern coast of France.
The maritime prefecture also indicated on Sunday that 71 other migrants were rescued in the Channel, but that some travelers on board the boat who did not request assistance were allowed to continue their journey.