LONDON, Aug 8 (Reuters) - The government said on Wednesday it had traced 6,000 potential immigration cheats through a new scheme to take fingerprints from visa applicants.

Since the system came into force last year, the government's directorate UKvisas said more than half a million sets of fingerprints had been taken from applicants.

That had led officials to match over 6,000 sets of prints "to individuals who are of concern".

"New fingerprint visas are fast becoming our first line of defence against illegal immigration," said home office minister Liam Byrne.

"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."

Fingerprinting is compulsory for British visa applicants from just under half of the countries of the world.

The prints are checked against government records to see if the individual is already known to the immigration authorities.

UKvisas said fingerprint checks had shown that one Sudanese businessman who applied for a visa to go shopping and holiday in Britain had been a failed asylum seeker in 2004 using a different identity.

Another Albanian applicant, who said he had never been to Britain before, was also found to be a failed asylum seeker after biometric checks were made.

By April 2008, the system will apply to all visa applicants covering three quarters of the world, the government said.

Controlling immigration has been a major political issue in recent years and a poll in April found that 82 percent of Britons did not think the government was in control of the situation.