Suella Braverman has suffered a collapse in personal support among the public in the wake of rows over a speeding fine and her handling of immigration, a poll for the Observer has revealed. With some Tories accusing the home secretary of positioning herself as a future leader, the latest Opinium poll found that her personal approval rating had slumped to -36 among voters. While 14% said they approved of the job she is doing, 50% said they disapproved. It is a significant decline in personal support since March, when 18% approved of her performance and 38% disapproved. Voters signalled frustration over her perceived lack of effectiveness in decision making and delivering on her policies. It is a blow for Rishi Sunak, who has made immigration numbers and his vow to “stop the boats” crossing the Channel one of his five priorities. There has been serious Tory angst after official figures last week revealed overall migration into the UK for 2022 was 606,000 – a record high. The prime minister has made competence and stability the top priority as he attempts to restore the government’s fortunes after the chaos that ensued during Liz Truss’s short time in office. However, he has opted to stick with his home secretary after questions were raised about whether she broke the ministerial code by requesting a one-to-one speed awareness course. According to the latest Opinium data, Sunak and Braverman performed poorly when voters were asked if they regard the pair as out of touch or representing what people think. However, Braverman performed significantly worse on trustworthiness, making big decisions, competence and “likeability”. Her net score for trustworthiness was -33 compared with Sunak’s -20, while her net score for being trusted with big decisions was -28, with Sunak scoring -11. The news comes as the Home Office announced the launch of an international campaign designed to dissuade potential migrants from attempting to cross the Channel, in its latest attempt to reduce the number making the dangerous journey. From this week, adverts in countries such as Albania will attempt to tell migrants directly that they will be detained and sent home or to a safe third country if they attempt the crossing. The Home Office said it would also highlight the serious dangers of the journey. The immigration minister, Robert Jenrick, will visit Algeria, Tunisia, Italy and France as the government frantically battles to meet Sunak’s pledge to effectively close the route. Jenrick said last night he wanted to “dispel myths about illegal travel to the UK, explain the realities, and combat the lies peddled by evil people-smugglers who profit from this vile trade”. Overall, 60% of voters said net migration was too high at present, with 19% saying it was about right. Adam Drummond, head of political and social research at Opinium, said: “Is Suella Braverman unpopular because the public disagree with her hardline views or because those who agree with her think she’s failing to put those views into practice? Unfortunately for the government it’s a hefty amount from both columns. “Yes, the home secretary’s negative ratings are in part down to very negative views among people who are unlikely to ever vote Conservative anyway, but among those who did vote for the party in 2019, her scores are far more negative than those for Rishi Sunak. Whether that is enough of a base to win the leadership in the event of the party going into opposition, though, remains to be seen.” It comes amid a fresh push from former Tory ministers to have international students taken out of the official net migration figures entirely. They claimed that voters had no concerns about those who came to Britain temporarily to study. A recent study found that the economic benefit international students bring to the UK has jumped by a third in three years, boosting the economy by an estimated £42bn in 2021-22. Jo Johnson, the former universities minister, said that after years of debate there was now a strong argument to count students separately. “Students aren’t migrants in the sense the public understands the term,” he said. “They’re here for a much shorter time than other categories of visa holders. The vast bulk of our international students are master’s students doing nine to 12-month courses. The overwhelming majority of students leave at the end of their studies and go home. “They are huge assets to our university system for well established reasons – they cross-subsidise research, they make it possible for universities to put on courses that otherwise wouldn’t be offered at all, thereby increasing choice for domestic students. They are not in tension with domestic students.” Nicky Morgan, a former education secretary, said: “As a former MP representing a university, I don’t think immigration concerns ever included students. If we took students out of the main number I think we’d have a much clearer idea of what is happening with our immigration system.” Meanwhile, Labour has said it would impose time limits on the hiring of overseas workers in shortage occupations to restrict immigration. Yvette Cooper, the shadow home secretary, told the Sunday Telegraph the party believes the measure would give an incentive to companies to train more British staff. The Labour frontbencher accused the Tories of presiding over a “huge gap between rhetoric and reality” on immigration. It forms part of Labour’s wider efforts to project a toughened stance on migration, with Sir Keir Starmer writing in the Sun on Sunday that hiring overseas workers on cheap wages is “no substitute for a proper plan”. The Labour leader suggested he would focus on apprenticeships as “a ticket to a better future” as he described the current system a “travesty” and said immigration must “come down”. • This article was amended on 28 May 2023 to correctly refer to Jo Johnson as a former universities minister, rather than a “former immigration minister” as an earlier version said.