Thames Valley Police has warned it may have to take officers off the beat if it is forced to police a second asylum centre in Oxfordshire.

In a letter to north Oxfordshire MP Tony Baldry, executive director of Thames Valley Police Authority Jim Booth claimed immigration minister Des Browne would not meet him. Neither had his predecessor, Beverley Hughes.

Mr Booth wants to discuss the authority's concerns about policing at Campsfield House immigration detention centre, near Kidlington, and a proposed 750-person asylum centre, between Piddington and Arncott, near Bicester.

He said police were already under additional pressure because of work on the Halifax House Animal Research Centre, being built by Oxford University, which has been targeted by animal rights activists.

He said: "The concern of the authority is to ensure that there are not only sufficient resources to provide safety to local communities and asylum seekers, but also to provide sufficient resources during the construction period."

Mr Booth said the force had previously asked for eight extra officers -- a sergeant and seven constables -- but had banked on Campsfield House closing.

The Home Office agreed funding for half that number, but later announced that Campsfield would not only be kept open, but expanded.

Mr Booth said: "The authority's concern is that the shortfall in resources would clearly have an impact on policing, not only in northern Oxfordshire, but in adjacent police areas as well."

Mr Baldry, who has written to Home Secretary David Blunkett about the issue, said: "There is quite clearly a very serious threat to policing levels across Thames Valley and it is astonishing that ministers are refusing to even discuss this with the police authority."

The Home Office was unavailable for comment.