Christopher Williams, also known as Peter May, was jailed for a third time when he was caught systematically stalking and spying on children just days after being released from jail for child abduction.

He was handed a 10-year sentence at St Albans Crown Court in June last year after being convicted of six counts of breaching a sexual offences prevention order (SOPO).

Williams, 42, of Parrots Field, Hoddesdon, who was previously jailed for eight years in 1998 after he was convicted of child abduction and indecent assault, was released from prison in June 2005.

Earlier, in 1991 he was jailed for abducting four-year-old Simon Jones of Hemel Hempstead from Gadebridge Park. Williams was sentence to 11 years in jail, which was later reduced to seven, but he was released in 1995.

Speaking about the latest court decision, Simon’s mother Sally Jones, said: “I just don’t understand it. If he had done the time he should have for taking Simon then the next family wouldn’t have had to go through what we did.

“He can’t control himself. We have to think of our children because they are defenseless against this type of person. It is just shocking.”

She said Simon, who is now 21-years-old, has never spoken properly about what happened to him but has moved on with his life.

She said: “Our children are not safe. Why should another family have to go through what we did?”

Within days of his discharge last year, Williams was spotted by a police detective following three young boys in Cheshunt, Hertfordshire.

His act of trailing the boys was a breach of the SOPO, which barred him from carrying on “any lengthy and sustained observation of children outside his home address”.

The prosecution alleged five further breaches against Williams, including incidents in which he “manoeuvred” his car so that it would be close by a group of children playing in a car park and another episode in Hoddesdon, in which he sat on a park bench in close proximity to five children.

Another breach consisted of Williams sitting in his car as he smoked a cigarette, adjusting his mirror so that he could have a clear view of a cluster of children playing in the street.

Williams’ case was heard at London’s Appeal Court last Thursday (July 12) in which he challenged both his 10-year sentence and the six convictions.

Lord Justice Dyson – sitting with Mr Justice Butterfield and Judge John Rogers QC – rejected Williams’ conviction appeal, but halved his prison sentence.

The judge said 10-years was clearly excessive in light of the fact that Williams had not harmed, or even touched, any of the children he watched.

Although his offences were deeply worrying, given his history, a 10-year sentence was more appropriate to punish an extreme sex-crime, he concluded.

Lord Justice Dyson said it was a “matter of huge concern” that Williams had committed his recent spying offences within such a short time of the SOPO order being imposed.

But he concluded: “Ten years for an offence of this kind – where the appellant did not even touch any of the children – was far too long.”

Mrs Jones said: “If it was one of their children it had happened to I think they would be a lot harder. He could have been planning something and although he hadn’t actually done anything a few weeks down the line he could have done something.”.