A rapist who sexually assaulted two young girls over a 12-year period has been jailed after he was assessed as posing "an imminent risk" of further sex offending against children.

John Myers subjected one victim to years of abuse before raping her as a teenager.

He also raped a second child when she was aged between 11 and 13.

The High Court in Edinburgh was told that Myers, 52, suffers from the condition of sleep apnoea and relies on a machine while in prison to "effectively keep him alive".

Myers, formerly from Tollcross, Glasgow, was earlier convicted of two charges of rape, attempted rape, sexual assault and indecent behaviour committed at addresses in the city between 2002 and 2014.

His catalogue of abuse was only uncovered after one victim was asked by a friend to share her "darkest secret".

When she revealed she had been a target for Myers' sex offending the friend shared the secret with one of her relatives who took the victim to report the abuse to the police.

Sentencing Myers to 13 years imprisonment, Lord Pentland told him the abuse of one of the victims, which began when she was aged five and culminated in rape, was "sustained and calculated".

Lord Pentland said: "The effect on your victims has been serious and lasting. I note you have evinced no remorse and not the slightest concern for your victims. The sexual abuse of children is repugnant."

He added part of the court's responsibility was to reflect society's abhorrence of such offending.

The judge said a background report prepared on Myers had assessed him "as presenting an imminent risk of future sexual offending against children".

He also ordered Myers should be kept under supervision for a further three years and told him he would be put on the sex offenders register for the rest of his life.

Defence counsel Brian McConnachie QC said Myers had previously acted as a carer for his wife.

He said Myers had attended a special needs school, adding: "From my discussions with him and my involvement with him he is clearly of limited intelligence."

The defence counsel said Myers had suffered health problems and was in remission after receiving treatment for prostate cancer.

He said Myers suffered from asthma, diabetes, high blood pressure and sleep apnoea for which he relied on a machine while in prison to "effectively keep him alive".

Mr McConnachie said Myers was well aware that following the jury's verdicts in his case there was no option but to impose "a substantial custodial sentence".