The court heard the abuse took place over two months

Iain Leslie, 52, admitted driving the 13-year-old girl to secluded areas and abusing her four times.

Leslie, of Muirends Croft, Munlochy, Ross-shire, was jailed for 10 weeks on Thursday and placed on the sex offenders' register for seven years.

Scotland's biggest charity for people with learning disabilities branded the sentence "outrageous".

Enable warned that it would not deter other offenders from preying on the vulnerable.

It acts as no deterrent that someone can engage in these practices and receive such soft treatment Mike Holmes Enable

Mike Holmes, the charity's director of campaigns, said: "What's particularly appalling is the leniency of this sentence. It's outrageous this guy got 10 weeks.

"Children are vulnerable but children with learning difficulties are particularly vulnerable.

"It acts as no deterrent that someone can engage in these practices and receive such soft treatment. This should have merited a more severe sentence."

Procurator fiscal Roderick Urquhart told Dingwall Sheriff Court that the girl, who suffers from attention deficit hyperactivity disorder, was particularly vulnerable and suffered from poor co-ordination and poor self-esteem.

Farm visits

Mr Urquhart told the court that the girl, who had developed an obsession with animals, went to visit Leslie at his farm to feed his calves.

Concerns raised by other members of the public about the visits led to social work and police inquiries, but nothing came of them at the time.

The court heard that when the girl's older brother found out that she had sneaked out of her house to meet Leslie after her parents had gone to bed, he decided to investigate.

This is the clearest case of grooming that I have seen for some considerable time Roderick Urquhart Procurator fiscal

Mr Urquhart said that after the offences came to light, Leslie's car was forensically examined.

He told the courts: "This is the clearest case of grooming that I have seen for some considerable time."

Leslie's solicitor John Robb told the court that his client's wife had decided to stand by him but the sheriff ignored his pleas for a sentence of community service.

Leslie admitted using lewd, indecent and libidinous practices against the girl on four occasions between 1 December, 2002, and 21 January, 2003.