Rishi Sunak has claimed Sir Keir Starmer is “another leftie lawyer” seeking to disrupt the Government’s immigration plans.

Labour leader Sir Keir was on the receiving end of the Prime Minister’s jibe after he accused the Government of delivering “utter failure” and warning the “problem just gets worse with every new gimmick”.

Sir Keir went on to criticise the Nationality and Borders Act 2022, which paved the way for the Government to try and send migrants to Rwanda – although this policy has stalled – and the latest legislation aimed at curbing Channel crossings.

But Mr Sunak told Sir Keir at Prime Minister’s Questions: “He asked about arrests, he asked about our laws. Actually when I was in Dover yesterday talking to our law enforcement officials, what did they tell me?

“Precisely because of the law that the Conservative Government passed last year they have now been able to arrest more than double the number of people they did before – 397 in the last six months.

“But stopping the boats is not just my priority, it is the people’s priority.

“But his (Sir Keir’s) position on this is clear: he wanted to, in his words, scrap the Rwanda deal; he voted against measures to deport foreign criminals; and he even argued against deportation flights.

“We know why – on this matter he talks about his legal background, he’s just another leftie lawyer standing in our way.”

Sir Keir, a former head of the Crown Prosecution Service, went on to highlight the number of people returned last year after they were deemed ineligible for asylum.

He said: “All that nonsense because he doesn’t want to answer the questions, because he knows what the answer is – the number is 21 people out of the 18,000.

“And what happens to the rest? They sit in hotels and digs for months on end at taxpayers’ expense.”

A Labour spokesman confirmed to reporters in Westminster on Wednesday that the party’s MPs would be instructed to vote against the Illegal Migration Bill.

Sir Keir had earlier opened the exchanges in the Commons by warning the Government’s Bill would drive a “coach and horses” through the country’s modern slavery framework that protects women from exploitation.

Mr Sunak replied by claiming Labour is in favour of “open door immigration and unlimited asylum, adding: “Whilst he may be on the side of the people-smugglers, we are on the side of the British people.”

MPs on both sides were told off by Commons Speaker Sir Lindsay Hoyle for heckling during the hostile exchanges.

Sir Keir suggested Mr Sunak would “steal our plan on stopping boats” if he was “serious” about responding to the issue.

The Prime Minister replied by claiming Sir Keir has been on the “wrong side” of the issue “his entire career”, adding: “He described all immigration law as racist. He said it was a mistake to control immigration. And he has never, ever voted for tougher asylum laws.

“It is clear while he is in hock to the open-border activists, we’re on the side of the British people.”

After the men exchanged further jibes, Sir Keir later claimed Mr Sunak was “absolutely deluded” to think his new plans would work.

He said: “They can’t say when they’ll fix the mess because it’s more talk, more gimmicks, more promises to be broken.”

Sir Keir went on to raise concerns over attempts to process the asylum backlog, with Mr Sunak saying action is being taken.

The Prime Minister highlighted return agreements with India, Pakistan, Serbia, Nigeria and Albania.

He added: “Our position on this is clear, if you arrive here illegally you will not be able to claim asylum here, you will not be able to access the modern slavery system and you will not be able to make spurious human rights claims. That is the right thing to do.

“But he’s going on and on about process, hiding behind process because he doesn’t want to confront the substance. We are the party of fairness and he represents the party of free movement.”

Sir Keir accused Mr Sunak of avoiding answering questions, adding: “On his watch, processing of those boat cases has gone from unacceptable, in his words, to almost non-existent.”

He went on: “After 13 years small boat crossings higher than ever, claims unprocessed, the taxpayer paying for hotel rooms, criminal gangs running all the way laughing to the bank and an asylum system utterly broken on his watch.

“This is their fifth prime minister, their sixth immigration plan, their seventh home secretary and after all this time all they offer is the same old gimmicks and empty promises.

“I don’t agree with the Home Secretary (Suella Braverman) on very much, but when she says that the Tories are all talk and no action she’s spot on, isn’t she?”

Mr Sunak told Sir Keir: “We’re doing what’s right, we’re acting with compassion, we’re acting with fairness and we’re acting to respect the laws and borders of our country.

“We’re delivering what we said and it’s crystal clear listening to this that it’s going to be the Conservatives and only the Conservatives that stop the boats.”

A spokesman for Sir Keir said Labour has a five-point plan for tackling the small boats crisis and said the party “clearly” wanted to stem the flow of those arriving in Britain unlawfully.

“The question is whether you think what the Government is proposing is going to tackle that effectively, and our view is that, as with their previous legislation, it isn’t going to do so,” he said.

The spokesman went on to confirm the party would oppose the Bill in Parliament.