Church leaders have backed a campaign to close down sick internet sites of the kind visited by killer Graham Coutts but believe police already have the powers to do so.

The heads of Sussex's Christian churches want to ban sites containing violent sexual images such as those watched by Coutts hours before he murdered Brighton teacher Jane Longhurst.

Churches Together, an umbrella group representing 1,000 churches across Sussex, believes the Government and police could use the Obscene Publications Act 1959 (OPA) to crack down on the internet but are not enforcing it strongly enough.

Coutts, 35, of Hove, was jailed for life for strangling 31-year-old Miss Longhurst on March 14 last year.

Ian Chisnall, mission and unity co-ordinator for Churches Together, said: "We believe many of the web sites mentioned during the recent trial are, in fact, illegal under English law.

"We have been in touch with children's charities and they say there is more that could be done. We want the Government to ensure the existing law is enforced more effectively.

"Great headway has been made in blocking or reducing the volume of child abuse images reaching the UK through technical measures.

"Similar levels of energy should be applied to adult sites."

The OPA says an image is considered obscene if "its effect is such as to tend to deprave and corrupt persons". It is illegal to publish such material.

Paul Hayward, of the Crown Prosecution Service (CPS) in Brighton, said: "Any child pornography is seen as obscene. Otherwise the CPS looks at the evidence of individual cases to see if they are obscene.

"What one person may regard as obscene may not fall within the definition in the Act."

While the Government can try to control material which originates in the UK, blocking images from abroad is more difficult. Many of the sites mentioned during Coutts' murder trial were created overseas.

Jane's mother, Liz Longhurst, launched a campaign last week to modify the 1959 Act to ban violent sex sites.

Churches Together has asked all Sussex MPs to sign a motion, tabled in Parliament by East Worthing and Shoreham's Tim Loughton, asking the Government to step up efforts to close the sites.

Mr Chisnall said: "We also encourage all internet service providers to follow the example of those such as AOL and BT Yahoo who have already taken steps to filter material from their mainstream services."