A teenage boy who sexually abused his little sister while babysitting had been watching online porn.
The 17-year-old repeatedly seriously abused the four-year-old child until the victim eventually told their mother what he had been doing.
She reported her son to the police and when interviewed the boy, who cannot be identified for legal reasons, admitted his behaviour had been 'disgusting and loathsome'.
Sentencing the youth, who is now 18, to three and a half years detention Judge Mark Brown described him as an intelligent young man who had known what he was doing was wrong.
He said: 'I am told you had been watching pornographic films.
'It is clear from what you said to police that you knew you had abused your sister and you appreciated that what you had done to her was not only disgusting but also loathsome but despite that knowledge you carried on and continued to treat her in that way.'
He said that the youth had treated her in a 'most appalling and dreadful fashion' because he had been sexually aroused.
The defendant had pleaded guilty to attempted rape and five offences of sexual assault.