AN AMNESTY for half a million illegal migrants could encourage even more economic migrants and asylum seekers to the UK, according to Kent MP and shadow immigration minister Damian Green.

The Ashford MP was responding to a hint by ministers that they might consider an amnesty for those who are in the country illegally.

Mr Green said the experience of other European countries suggested such amnesties only encouraged more people to make their way to them.

He said: "Our borders are very badly protected as it is and an amnesty could lead to an uncontrolled increase in numbers coming here.

"The experience from other countries is that amnesties do encourage more people to arrive illegally and that once you have had one, it is very difficult to avoid having others.

"People would no doubt think they can chance their arm and that has happened in countries like Spain and Italy."

Immigration minister Liam Byrne told members of the home affairs select committee on Tuesday that he had commissioned some analysis on the subject but it was "too early to tell" whether he would allow such a move.

Supporters of an amnesty say that there is no realistic hope of ever deporting 500,000 asylum seekers and that allowing undocumented migrant workers to remain could raise £1billion in tax revenue.