At least 6,000 suspect individuals have been caught through the Home Office's new fingerprint visa scheme.
The scheme was introduced last year as part of the government's plans to virtually expand the UK's borders - designed to stop certain individuals entering the UK before they leave their home country.
Since the scheme was introduced more than a million sets of fingerprints have been taken from people applying for visas, official figures released today show.
All were checked against records in the UK - looking for, among others, failed asylum seekers and suspected terrorist - and 6,000 were matched to what the Home Office terms "individuals of concern".
Home Office minister Liam Byrne said: "New fingerprint visas are fast becoming our first line of defense against illegal immigration.
"By collecting fingerprint information on foreign nationals coming to the UK in advance of their journey, we are building a new overseas border control which is flushing out the false visa applicants"
Foreign nationals from nearly half of all countries are now subjected to compulsory fingerprinting when applying for a UK visa. By April 2008 the Home Office wants to extend this to three-quarters of the world's population.
Foreign & Commonwealth Office minister Kim Howells continued: "Recording biometric information allows us to fix an individual's identity at the earliest point practicable and track their future dealings with the UK.
"In the past year, we have started to introduce biometric data collection technology to the visa application process. This is a key part of our objective of strengthening our borders."
Last month Gordon Brown announced the creation of a new uniformed border force, designed to further strengthen the UK's borders.
The prime minister said this would improve coordination between customs and excise and immigration.
The Conservatives claimed this was a watered-down version of their own border police force, which they argued would have more powers and resources.
The Tories have used today's visa figures to restate their call for an annual limit on economic migrants.
They say the number of visas granted last year rose eight per cent and attribute this rise to the expansion of Europe.
Shadow immigration minister Damian Green said: "This is why Conservatives are calling for an explicit annual limit on economic migrants from outside the EU so the government can respond to real world conditions".