A former senior aide to David Cameron has denied charges of making and possessing indecent images of children.

Patrick Rock, 63, pleaded not guilty at Southwark crown court in London to seven offences related to photographs of children as young as 10 found on his iPad last year.

Rock, who was one of the government’s chief advisers on online pornography filters, is accused of six counts of making indecent images of children and one charge of possessing 56 indecent images of children.

The charges relate to 31 July to 31 August 2013 when Rock was in the US. The images show girls aged approximately 10 to 14. They have been classified by Crown Prosecution Service lawyers as level three, the lowest category.

Rock was arrested at his home in February. He resigned from his post as deputy head of Cameron’s policy unit after his arrest, which was not made public until the details were published by the Daily Mail three weeks later.

The offence of making indecent images of children carries a maximum sentence of 10 years’ imprisonment under section 1 of the Protection of Children Act 1978. Possessing child abuse images has a statutory maximum of five years’ imprisonment under section 160 of the Criminal Justice Act 1988.

Rock was bailed to return to Southwark crown court for a pre-trial hearing on 27 February. Under his bail conditions, Rock must surrender his passport to police, reside at his home in Fulham, west London, and maintain contact with a welfare officer.