Net migration to the United Kingdom soared to more than 900,000 last year, although tougher visa rules have started to reduce the number of arrivals, official data showed.

Data from the Office for National Statistics on Thursday showed net migration of 906,000 for the 12 months to June 2023, revised up from the previous estimate of 740,000, in what the ONS described as “unprecedented levels” since 2021.

Numbers fell 20 percent from the record high to 728,000 for the year to June 2024, the ONS said, driven by declining numbers of dependants coming with those on study visas after the rules were changed.

Voters in the UK – whose overall population is approximately 68 million – have expressed concern that the large number of arrivals could worsen housing shortages and put further strain on public services.

But employers in sectors such as healthcare say they cannot function without foreign workers.

High levels of legal migration in 2016 was one of the driving forces behind the UK’s vote to leave the European Union.

In the year ending June 2016, the last twelve-month period before the Brexit vote, net migration stood at 321,000.

While post-Brexit visa changes saw a sharp drop in the number of EU migrants to the UK, new work visa rules led to a surge in immigration from India, Nigeria and Pakistan, often to fill health and social care vacancies.

The jump to a record level in 2023 came under the previous Conservative government, which had promised to cut migration and did introduce measures to curb students and care workers from bringing their family members.

The current Labour government, elected in July, has also said it wants to reduce numbers by training workers to fill skills gaps. It blamed the record rises on the Conservatives.

Migration Minister Seema Malhotra said that the government was committed to “ensure those who abuse our immigration system face the strongest possible consequences”.

“No longer will employers be able to flout the rules with little consequence or exploit international workers for costs they were always supposed to pay if they choose not to recruit domestically,” she added.