100 foreign nationals on run from detention

In the last four years, nearly 150 inmates broke out of secure centres used to hold illegal immigrants and foreign national prisoners. But of those only 40 were found by the police and returned to custody.

Ministers revealed the escapes in answers to questions laid in Parliament by the Tories.

Tory immigration spokesman Damian Green said the figures were "alarming" and called for an explanation from the Government.

He said: "These are meant to be secure institutions. Why are so many people allowed to escape back onto the streets?

"Ministers need to explain this latest failure."

The Home Office figures showed 148 people absconded from immigration detention centres since 2006. Figures for earlier years are not available.

In one year alone 90 went missing. Of those who escaped in 2007, 71 are still at large and only 19 have been found.

There are 11 immigration removal centres in the UK, including two at Gatwick Airport and two near Heathrow.

They hold up to 3,000 inmates including foreign national prisoners, illegal migrants and failed asylum seekers who are due to be deported or are having their cases reviewed.

Immigration Minister Phil Woolas said: "Detention is a vital tool and without it we would not have been able to remove record numbers of foreign national prisoners – more than 15,000 in last three years.

"We have tightened security at our immigration removal centres and escapes have declined significantly."