Net migration could hit a record 700,000 when figures are released this week

Internal Home Office forecasts suggest that the official net migration estimate – to be published on Thursday – will rise to a record level.

The figure for the year to June is expected to top 700,000, beating the high of 606,000 for 2022, sources said.

The 700,000 figure is based on the Home Office's own data on immigration arrivals – such as the number of visas awarded – and an estimate of emigration. However, the official Office for National Statistics (ONS) figure may vary due to changes to methodology.

One factor behind the expected increase is a sharp rise in the number of foreigners extending their UK visas.

Home Office data shows a 50 per cent increase in the number of foreign nationals who successfully applied to extend their permission to stay in Britain.

There were an extra 105,000 visa extensions for work, study or family reasons in the first six months of this year. The total rose 49 per cent to 319,979 in first half of this year compared with 214,899 in the same period last year.

This rise was mainly due to foreign workers winning new visas to stay in Britain – an increase of nearly 103,000.

It means many temporary migrants are staying in Britain for longer than expected – a factor likely to contribute to an overall rise in net migration.

In addition, the overall number of work visas handed out in the year to June was up 45 per cent, Home Office figures published in August showed.

Net migration is notoriously difficult to predict, due to ever-changing methods deployed by the ONS.

Earlier this year, the Centre for Policy Studies think-tank forecast net migration of between 700,000 and a million for 2022 – but changes to ONS methodology led to the official estimate of 606,000.

The ONS has again changed the way it calculates net migration for the figure to be published this week. It will also issue revisions to its immigration estimates from 2012 to 2021, and separate revisions to its figures for last year.

In June, the Migration Watch UK think-tank calculated the UK population would soar to up to 87 million by 2046 if net migration continued at the same rate, requiring 15 new cities the size of Birmingham.