William McNeil, 41, of Waterside, Hadfield, pleaded guilty at Derby Crown Court to sexual activity with a child.

His lawyers successfully argued there was no need for a longer than usual sentence as it had been 15 years since McNeil last offended.

The Court of Appeal cut his four-year jail term to two-and-a-half years.

Previous offences

Sir John Alliott, sitting in London with Mr Justice Treacy, heard that McNeil pleaded guilty at the earliest opportunity to performing a sex act on a 15-year-old boy he had met on a bus.

Sir John ordered the term be cut to what he would have been given in normal circumstances.

The court heard McNeil met the boy on a bus to Glossop in October last year, and they shared the back seat. They shared a cannabis cigarette and got off at the same stop.

McNeil offered the boy more cannabis and they went under a bridge together to smoke it. McNeil encouraged the boy to pull down his trousers and performed a sex act on him.

'Prime mover'

The distressed teenager ran to a nearby shop and complained about what happened and the police were called.

McNeil, found on a bench surrounded by bags of drink and food, claimed the boy had instigated the incident and said he thought he was over the age of 16.

Sir John added McNeil had convictions for sex offences dating back to the 1980s, and had been before the courts in England and Scotland.