The latest official figures on immigration to the UK will be published today.
Focus will fall on whether estimated net long-term migration - the difference between the number of people arriving in the country and leaving- remains around record levels.
The Office for National Statistics will publish provisional figures on the measure for the year to June.
In the 12 months to March, net migration dipped slightly to an estimated 327,000 - but it remained close to peak levels and more than three times the Government's target.
The Tories' aim of reducing net migration to below 100,000 has attracted intense controversy.
The new figures are also likely to spark fresh debate over the issue of immigration in the context of the Brexit vote.
Britain is expected to seek to introduce controls on free movement following the referendum outcome, with the details of any future system yet to be outlined.
On Wednesday a parliamentary committee heard that ending the free movement of low-skilled workers from the EU into the UK could see businesses close, food prices rise and social care cut.
The Lords EU Home Affairs Sub-Committee was told that a work permit system would be the most practicable option for controlling migration, but registering the up to 3.9 million EU nationals already resident in Britain would be a "formidable" task.