The British government said it was reviewing security procedures after a hoax caller claiming to be the director of Britain's GCHQ eavesdropping agency was put through to Prime Minister David Cameron. The Sun newspaper said the drunk caller had earlier tricked the intelligence agency into handing over a mobile phone number for its director Robert Hannigan, although the government said it was not one used for calls involving classified information. "The Prime Minister ended the call when it became clear it was a hoax," a spokeswoman for Cameron's office, 10 Downing Street, said in a statement about the calls on Sunday. Both GCHQ and Number 10 take security seriously and both are currently reviewing procedures following these hoax calls to ensure that the government learns any lessons from this incident." The Sun reported that the unnamed man, who it described as being well-spoken and in his 20s, had called GCHQ in the early hours of Sunday pretending to be a Downing Street aide and saying Hannigan was required to attend an emergency meeting.