Britain will unveil changes to its legal migration system on Monday after official statistics showed that annual arrivals had hit a record high last year, putting pressure on Prime Minister Rishi Sunak who had promised to bring them down.

Sunak's spokesperson said that the prime minister believes net migration to the country is too high and needs to be reduced "significantly".

Britain's interior minister James Cleverly will give a statement to parliament later on Monday "detailing further measures to bring down levels of legal migration and stop abuse of the system," Sunak's spokesperson said.

Annual net migration to the United Kingdom hit a record of 745,000 last year and has stayed at elevated levels since, data showed last month, putting political pressure on Sunak to act to reduce it in the run up to an election expected next year.

"We think the numbers are too high, they do need to reduce significantly and in the short term," Sunak's spokesman said.

"The evidence we have is that some of the people coming across, particularly dependents, aren't actively contributing to the workforce in any substantive way."

(Reporting by Alistair Smout. Editing by Andrew MacAskill and Sarah Young)