A dangerous Norfolk sex offender who raped a six year-old girl has been given a 22 year extended sentence and placed on the sex offenders' register for life.

Keith Butterworth, 60, who is already serving a four-and-a-half-year sentence for child sex offences, was convicted following a trial at Norwich Crown Court of a further offence of raping a child.

Butterworth, who previously lived in the Thetford area but is now in HMP Bure, was given an extended sentence of 16 years in jail and six years on extended licence for his latest offending.

William Carter, prosecuting, said Butterworth had been assessed in reports as a posing a danger to children and had committed the offence on the girl after grooming her family into trusting him.

Mr Carter said he allayed their fears by saying that he had been vetted and had been CRB (Criminal Records Bureau) checked as he had worked with the elderly, so he was able to win their trust so as to be left alone with the child.

'He showed a significant degree of planning and grooming behaviour not only against the young victim but also her family.'

He said the abuse by Butterworth had a profound effect on the victim and her family and in an impact statement the victim's mother said it had 'ruined her life.'

Sentencing him, Judge Stephen Holt said he posed a high risk of serious harm to the public, especially young children.

He said he had displayed a 'significant degree of planning and grooming behaviour' and had fooled the victim's family.

He said the victim and her family had been 'deeply damaged' by what happened and Butterworth had betrayed their trust.

Judge Holt said: 'People in society should expect to trust older people with their children. You betrayed that trust.'

Wayne Cleaver, for Butterworth, said the rape was committed in the same offending period of the other offences for which he was jailed in 2016.

He said it was not a case where he had been released from a sentence only to re-offend but was part of a course of conduct.

He said had all the matters been dealt at his previous sentencing the judge would have considered totality of any sentence.