Net migration figures due on Thursday are predicted to drop to pre-Brexit levels of about 300,000, according to a thinktank.

British Future, which calculated the drop in overall migration, also found that most Britons remain unaware of the falling numbers, and expect the figures to rise or stay the same.

Last week, the Office for National Statistics (ONS) said its updated estimates, which include a more accurate count of emigration by British nationals, showed a higher and earlier peak in net migration of 944,000 in the year to March 2023. It had previously estimated that net migration peaked at 906,000 in the year to 30 June 2023.

Using new methodology, the figures show cumulative net migration over the period from 2021 to 2024 was about 97,000 lower than previously thought.

The ONS now estimates that net migration fell to 345,000 in the year to December 2024, as emigration by UK nationals increased.

By examining UK visa data, British Future believes the figures will drop further – but the continued drop is not being registered by the UK population.

New research published by Ipsos/British Future found that only 16% of the public expect net migration to be lower in one year’s time, despite net migration halving last year and continuing to fall.

More than twice as many people (38%) expect net migration to increase, with 31% expecting it to remain the same.

Most of the public also thinks net migration increased last year, according to the research – when in fact numbers halved.

The new findings from the Ipsos/British Future Immigration Attitudes Tracker show that 56% of the public thinks immigration increased last year.

Government proposals released last week outlining restrictions on settlement and benefits for those coming to the UK are more restrictive than most of the public would choose, the research finds.

Half (50%) think migrants working in graduate-level jobs should only wait five years or less before qualifying for settlement, and 53% think those doing mid-skilled jobs should wait less than 10 years.

Dissatisfaction with how the government is dealing with immigration is at 56% – an increase from 48% last summer, though still lower than the 69% who felt dissatisfied with the Conservative government in the February 2024 tracker.

skip past newsletter promotion

Our morning email breaks down the key stories of the day, telling you what’s happening and why it matters

Privacy Notice: Newsletters may contain information about charities, online ads, and content funded by outside parties. If you do not have an account, we will create a guest account for you on theguardian.com to send you this newsletter. You can complete full registration at any time. For more information about how we use your data see our Privacy Policy. We use Google reCaptcha to protect our website and the Google Privacy Policy and Terms of Service apply.

Of those who are dissatisfied, the most common reason given – by 73% of dissatisfied respondents – is: “The government is not doing enough to stop migrant channel crossings.” The other top reasons given are “being too generous to migrants/asylum seekers”, (65%) and “allowing too many people to claim asylum in Britain” (63%).

Sunder Katwala, director of British Future, said: “Net migration is falling, with today’s figures likely to show another drop towards pre-Brexit levels of around 300,000 – yet our political debate hasn’t caught up. As numbers move closer to ‘normal’ levels, politicians can’t just keep competing over who will cut them further.

“The risk for Keir Starmer’s government, which is promising to get a grip on numbers, is that constant crisis messaging only reinforces the public belief that asylum and immigration are out of control.”

The Home Office has been approached for comment.

The figures will be released hours after it emerged that the Home Office will have to spend a further £1.4bn because of a rise in the number of people arriving in the UK on small boats.

The OBR document, which was released before the budget on Wednesday, said that there will be £1.4bn of “additional pressure” on the Home Office’s budget because of a near 20% rise in the number of small boat arrivals and an 8% increase in asylum seekers in supported accommodation.