A SEX offender convicted of abusing children in Dumbarton and Helensburgh had his sentence cut from 12 years to four.

Robert Fury, 51, successfully appealed against three of the 11 charges on which he was convicted last year.

Fury was found guilty at the High Court in Glasgow in April 2015 of five charges of assault, five charges of using lewd and libidinous practices and one charge of rape, committed between 1976 and 2002 at houses in the two towns.

The following month he was sentenced to 12 years in prison for the crimes – a term backdated to June 2014, when he was first placed on remand.

Appeal judge Lady Smith, sitting with Lady Dorrian and Lord Bracadale at the appeal court in Edinburgh, decided a submission of “no case to answer” by Fury’s defence QC during last year’s trial should have been upheld.

The three charges thrown out by the appeal judges related to the rape, said to have been committed on a 17-year-old in 1991, and allegations of sexual assault against girls aged under 16 between 2000 and 2004.

Brian McConnachie QC, defending Fury, had argued during the trial that the so-called “Moorov doctrine” – which allows for mutual corroboration of incidents, as a result of similarities in the way they occurred – had not been properly applied because of the time between the alleged offences.

That argument was rejected by the trial judge, Lord Kinclaven, but was accepted by the three appeal judges.

Lady Smith wrote that there were “no special or extraordinary features” between the charges on which Fury appealed, and said: “There were also dissimilarities, there was no explanation for the substantial lapse of time and the later events were not the first opportunities to resume the alleged course of conduct.

“Accordingly, we consider that the appeal is well founded. There was no proper basis on which the jury would have been entitled to infer the necessary underlying unity of intent; ‘Moorov’ could not apply.

“The submission of no case to answer ought to have been upheld.

"It follows that there was no proper basis on which the appellant could be convicted of charges 7, 8 and 9 and we will quash those convictions.”

Long-term inmates – those sentenced to four years or more – can apply for release after half their term, but the decision on whether to grant the request lasts with the Parole Board.

That means Fury could, in theory, be freed from prison this month.

But a Parole Board spokesman said the organisation could not comment on individual cases.

New rules on automatic early release, which came into effect in Scotland in February, mean offenders must serve the whole of their jail term if the courts have ruled they must be supervised on their release.

Those who do not require supervision will be freed six months before the end of their sentence. Fury remains convicted of five charges of sexual assault and three charges of lewd and libidinous practices.

Sentencing Fury last year, Lord Kinclaven said: “You have been found guilty of a serious catalogue of offending.

"It started at the age of 12 and your last offence was committed when you were 39. The court has to mark the seriousness of your offending.”