Keir Starmer was under attack from left and right on Thursday after he set out plans to stop small boat Channel crossings in Labour’s first big intervention on the issue. Fleshing out his party’s proposals, the Labour leader promised to ditch the use of barges, hotels and military sites to house asylum seekers. He also promised to recruit 1,000 caseworkers to end the asylum backlog. But the announcements followed a day of bitter exchanges with Rishi Sunak and the home secretary, Suella Braverman, after Starmer conceded that Labour could strike a deal to accept a quota of asylum seekers from the EU in exchange for closer cooperation to tackle people smugglers. Labour also announced plans to treat criminals involved in cross-Channel people-smuggling as terrorists and labelled those who disagreed with the proposals “un-British”. Those remarks enraged a union leader, charity bosses and Labour MPs, who called for Starmer to stop appealing to anti-migrant sentiments. Matt Wrack, the president of the TUC, told the Guardian that Starmer was in “danger of pandering to rightwing Tory rhetoric” on immigration. “It’s kneejerk to label those who raise these concerns as ‘un-British’,” he said. “Labour must offer a sensible alternative to the inflammatory approach of Tory ministers” Sile Reynolds, the head of asylum advocacy at Freedom from Torture, said: “In an effort to outdo the government’s enforcement posturing, Labour risks obscuring the positive commitment it has made to consider the asylum claims of all those arriving on our shores, no matter how they get here. “The ‘war on smuggling’ rhetoric is not a serious solution.” Steve Smith, the chief executive of Care4Calais, said: “Today was an opportunity for Keir Starmer to inject some decency and compassion into the debate around refugees. Instead, he chose to mirror the gimmicks and divisive rhetoric employed by the Conservatives. “‘Smash the gangs’ may get him a headline in the Sun, but it’s not a plan.” One senior Labour backbencher said they were concerned about the “authoritarian framing” of the debate by the Labour leader. “It’s not ‘un-British’ to have a difference of opinion with Keir Starmer,” they said. “We need more tolerance of differences of opinion in our politics, especially in sensitive matters like migration.” Starmer indicated he could strike a deal with Brussels that would involve the UK taking a quota of asylum seekers who arrive in the EU in exchange for the ability to return people who cross the Channel. He insisted that his focus was on ensuring that an anti-terrorism-style international crackdown could “smash” the gangs behind the “vile” trade. Sunak seized on the proposal, claiming it could result in 100,000 EU migrants coming to the UK every year. On a visit to Devon, the prime minister told reporters : “I think he [Starmer] spent most of last year voting against a previous bill which has since then led to almost 700 arrests related to organised immigration crime, so I don’t think it’s credible that he really wants to grip this problem.” Braverman said the UK would become a “dumping ground” for Europe’s migrants. Starmer said their response was “typical from a government that’s completely lost control of the situation”. “It’s embarrassing that the government is pumping out this nonsense,” he added. Labour sources said Braverman’s attack raised questions over the government’s own policy towards pursuing an EU returns deal. In August, Downing Street said the prime minister “remained open” to an EU-UK returns deal. Labour’s plans also include recruiting more than 1,000 Home Office caseworkers – a 50% increase on current staffing levels – to end the asylum backlog, which the shadow home secretary, Yvette Cooper, said would end the use of hotels and other sites. Labour is also promising to fast-track decisions on applications from “safe” countries, namely Albania and India, and create temporary “Nightingale asylum courts” to speed up legal challenges. A returns unit, backed by 1,000 staff, would also be created by Labour to triage and fast-track removals. As part of its plans, Labour said it would work to reach an agreement to share real-time intelligence with the EU similar to the Schengen information system II, a database of terror suspects and immigration offenders which the UK had automatic access to before Brexit. The party has also promised to strengthen powers to restrict the movement of people smugglers by making it quicker and easier to obtain serious crime prevention orders, which are used to target offenders such as terrorists and drug traffickers. Cooper said: “Tory chaos at our borders and in the asylum system is costing taxpayers billions and must come to an end. All we have had from this government is gimmicks, not grip. “Labour has a serious plan to end the government’s wasteful spending on hotels and return people who have no right to be here. “Labour will take back control of our asylum system. We know the British public want to see strong border security and a properly controlled and fair asylum system, and that’s what we’ll deliver.” Downing Street said the government was open to an EU-wide returns agreement, but would not accept a quota of migrants in exchange. Taking a hardline stance on immigration crime will be seen as important to convince swing voters that Labour can be trusted to stem the number of Channel crossings, which has reached more than 23,000 so far this year.