Britain is setting up a computer database to track down around 150,000 people who are staying in the country illegally, a media report said Wednesday.
Border officials will launch the project next month to deal with a huge backlog of foreign nationals who have overstayed their student or temporary work visas, the Daily Mail reported.
Passenger records held in the database, which will cover details of all flights outside Europe to and from Britain, will be checked. There will be careful monitoring of around 100 migrants whose visas expire daily.
Letters will be sent to the illegal migrants, warning them that they will be deported and barred from entering the country if they do not leave within 28 days.
G4S, the security firm which failed to deliver enough staff for the Olympics, is also among the private companies submitting tenders for the multi-million pound contract.
Immigration Minister Damian Green said a third of people decide to overstay at the point their visa expires.
The UK Border Agency (UKBA) recently launched a drive to remove visa "overstayers" that led to thousands being removed. Around 2,000 were removed from London alone.
The majority of those targeted entered the country on student visas which have now expired.
Green said they mainly came from India, Pakistan, Bangladesh, China, Brazil and Nigeria and were now working illegally.