A man has admitted sexually assaulting a teenage boy and sexual activity with a child under 16.

David Keen, 29, pleaded guilty on the day his trial was due to start at Lewes Crown Court.

He also admitted nine offences relating to sexual activity with a 13-year-old boy from Australia.

Keen, of Bognor, has now pleaded guilty to 28 matters in total.

These range from possessing, making and distributing indecent images of children, to sexual activity with children under 16, and conspiracy to commit such offences.

He was found in possession of more than 5,000 indecent images of children.

His co-defendant John Churchley, 59, of Littlehampton, has pleaded guilty to 15 offences.

Churchley was in possession of more than 25,000 indecent images of children.

Sentencing of Keen has been adjourned for reports and the next hearing for both men will be on May 19.

It is expected they will both be sentenced on July 12.

DI Jeff Riley, Major Crime Branch, who has led the investigation, said: "We are working with a number of partner agencies to support the children who came to notice during the investigation, as well as their families, and this support will be given to anyone else who may be coming forward.

"We are in possession of a small number of identifiable images of young men whom may be additional victims of David Keen. We encourage them to make contact even at this late stage. We can provide support to them and I ask them if they have been a victim of abuse in relation to this matter or any other to contact their parents, a professional they trust or Childline on 0800 11 11 for support and advice. Alternatively they can contact police direct on 0845 6070999 and quote Operation Addition."