Most illegal immigrants caught trying to enter Kent through the Channel Tunnel no longer have their fingerprints taken.

The move is said to have given border staff at the Eurotunnel terminal in Coquelles, north of Calais, more time to search vehicles for offenders.

But it has been attacked by shadow home secretary Yvette Cooper, who said people would be given the impression they should "feel free to keep trying" to enter the UK illegally.

The revelation was made in a letter to Roger Gale, the MP for North Thanet, by one of his constituents, who works at the UK Border Agency.

After putting the allegations to the immigration minister and Ashford MP Damian Green, he was told fingerprinting was no longer routine practice at Coquelles.

Mr Gale said: "I've since had an email from a former immigration officer now living in Paris, who says that between 2005 and 2007, there was a clear message being sent out that immigrants shouldn't be photographed or fingerprinted because it might upset them.

"His view was that the borders leaked like a seive. That was five years ago and it would appear not a great deal has changed, except possibly for the worst."

The revelation comes just months after it emerged passport checks were relaxed last summer.

That led to the resignation of UKBA chief Brodie Clark and forced home secretary Theresa May to offer an explanation in a speech to the House of Commons.

Asked if the country's borders were still safe, Mr Gale added: "I think they are, but I think the operation of the UK Border Agency leaves a great deal to be desired.

"Quite clearly, it hasn't been working as effectively as it can or should have been."

A UK Border Agency spokesman said: "We work very closely with the French authorities to counter illegal migration - all clandestines are handed straight to the French border police.

"Our controls across the Channel continue to show significant improvements with a 70 per cent reduction in the number of attempts to cross illegally between 2009 and 2011."