LONDON: Net migration to the UK hit a record high last year, official figures showed Thursday, heaping pressure on Conservative Prime Minister Rishi Sunak who has vowed to reduce new arrivals.

Immigration — long a vexed political issue in Britain — is set to be a key issue in a general election expected next year, which the main opposition Labour Party are currently favourites to win.

The Office for National Statistics (ONS) said net migration — the difference between the number of people arriving in Britain and those leaving — was 745,000 in 2022, higher than previously thought.

It revised the figure upwards by 139,000 from what was already a record when released in May, citing “unexpected patterns” in the behaviour of migrants.

Sunak has long described regular immigration levels as “too high”. His party won a landslide under the leadership of Boris Johnson at the last election in 2019, largely on a promise to bring net migration numbers down.

The Conservatives have repeatedly promised that leaving the European Union, which ended the free movement of people from member states, would allow the UK to “take back control” of its borders. But legal migration has soared since Britain formally left the EU in January 2020. In 2021, net migration was 488,000.

Some Tory backbenchers urged Sunak to “act now” to cut net migration and meet the party’s 2019 pledge.

“This really is ‘do or die’ for our party,” the New Conservatives group of right-wing lawmakers said in a statement.

A spokesperson for Sunak said it was clear net migration “remains far too high” and hinted that further measures to reduce it were on the horizon.