By politics.co.uk staff
A senior adviser to David Cameron who worked in Downing Street has been arrested over child pornography offences, it has emerged.
Patrick Rock, 62, deputy director of policy in No 10, was arrested at his home last month, No 10 said in a statement.
He had worked on a number of policy issues across government, including the online pornography filter.
"On the evening of February 12th, Downing Street was first made aware of a potential offence relating to child abuse imagery. It was immediately referred to the National Crime Agency," the statement said.
"The prime minister was immediately informed and kept updated throughout. Patrick Rock was arrested at his home in the early hours of February 13th, a few hours after Downing Street had reported the matter."
Cameron and Rock have known each other for years, having worked together for former home secretary Michael Howard in the 1990s.
He had been tipped for a peerage, despite being photographed with a dossier of the coalition's broken promises outside No 10 last year.
"Subsequently, we arranged for officers to come into No 10 and have access to all IT systems and offices they considered relevant," the Downing Street statement added.
"This is an ongoing investigation so it would not be appropriate to comment further, but the prime minister believes that child abuse imagery is abhorrent and that anyone involved with it should be properly dealt with under the law."
The Mail newspaper reported a source close to the prime minister saying he "never expected anything like this".
Rock had failed to get elected as an MP during the 1970s and 1980s despite several promising opportunities to do so – including the 1984 Portsmouth South by-election in which the SDP-Liberal alliance candidate Mike Hancock unexpected overturned a Tory majority of over 12,000.
Hancock was suspended by the Liberal Democrats last month over claims of sexual misconduct in his office.