Illegal immigrants are being released by Hertfordshire Constabulary and being given directions to the nearest immigration office, according to information obtained under the Freedom of Information Act.

Figures obtained by the Conservative Party show ten out of 27 police forces, including Hertfordshire's, are telling officers not to arrest or detain the immigrants, but instead give them instructions on how to get to the correct immigration centres if the Immigration Agency is unavailable to pick them up.

James Clappison, MP for Hertsmere, said: "I know this has been happening over the years. I don't think this arrangement is satisfactory and I think most people would agree.

"But it is a national issue and it is not fair to single-out Hertfordshire. I want to know what the Government is doing about this."

But Hertfordshire Constabulary said illegal immigrants are not left unaccompanied and are taken to detention centres under supervision.

A spokesman for the force said: "Officers in Hertfordshire are issued with guidance in dealing with illegal immigrants. This specifies that all adult males identified from lorry drops, or any illegal immigrant who may have committed an offence, will be transported to a regional immigration reception centre, where they will be fully interviewed before being moved on, either into further detention or approved accommodation. The Border and Immigration Agency will collect detainees from police custody."