A convicted sex offender suggested he and a teenage girl - who turned out to be an adult decoy - watch Harry Potter before embarking on a sexual relationship, a court has heard.

Sean Denniston, who has a previous conviction for a child sex offence, repeatedly messaged who he thought was a 14-year-old on Facebook despite telling her he had a fiancee.

Norwich Crown Court heard the 34-year-old and the decoy exchanged selfies with each other before Denniston went on to suggest they meet up and see a Harry Potter film and also visit "Harry Potter land".

Norwich Crown CourtNorwich Crown Court (Image: Peter Walsh, Newsquest) Lynne Shirley, prosecuting, said Denniston told the decoy they should meet up in Walcott where he lived as part of repeated communication which went on for five weeks.

She said Denniston told the girl they should keep their communication a "secret" telling her she should say she was a "friend of his niece" if she was asked by his partner.

Denniston asked her if she would have sex with him and suggested they do it when her mother was not at her home in Norwich.

He asked her if she would be "up for it" and told her he would be "gentle".

Miss Shirley said on July 16 this year members of the paedophile hunter group attended his address and alerted police.  

Denniston, of Ostend Road, Walcott, appeared in court for sentencing on Friday having admitted attempted sexual communication with a child between June and July this year.

Sean DennistonSean Denniston (Image: Norfolk Police) He also admitted being in breach of a Sexual Harm Prevention Order (SHPO).

Jailing him for 30 months, Recorder Paul Garlick said these were "serious offences" made more serious by his previous offences. 

Lori Tucker, mitigating, said Denniston, who deserved credit for plea, had a problem with alcohol - which was at the root of his offending - and has suffered from non-epileptic seizures.

She said as it was an adult decoy Denniston had been communicating there was no actual risk of harm.

But she accepted there must be some harm as Denniston thought he was dealing with a child.

Denniston was also made the subject of an indefinite Sexual Harm Prevention Order (SHPO) and also put on the sex offenders register indefinitely.