A HOAX caller, pretending to be the head of Cheltenham-based spy agency GCHQ, was put directly through to Prime Minister David Cameron, but officials claim no confidential information was exchanged.

The call followed a separate security lapse earlier in the day when a caller was given a mobile number for GCHQ director Robert Hannigan after he rang the organisation.

Later, a caller rang Downing Street pretending to be Mr Hannigan and was put through to the Prime Minister on an official mobile phone.

Mr Cameron eventually hung up after a ‘quite brief’ conversation when he realised he was the victim of a hoax call.