Richard Tallis, 54, of Bolsover Road, West Tarring, appeared at Portsmouth Crown Court on Friday (July 30), having pleaded guilty at a previous hearing to six counts of sexual assaults on a girl between seven and 15 years ago.
He was jailed for 17 and a half years, police confirmed.
The prosecution, authorised by the CPS, followed an investigation by West Sussex Safeguarding detectives, who worked with local authority childrens’ services to ensure that no children were at any further risk.
Detective Constable Angela De Vivo of the West Sussex Safeguarding Investigations Unit said: “Tallis had systematically abused this very young girl over several years, causing her deep and lasting distress.
“Only three years ago did she feel strong enough to come forward and report what had happened to her.
“We admire her courage and resolution in doing so and in supporting our investigation all the way, and in being ready to give evidence if needed.
“Please contact us at any time if you or anyone you know has been the victim of such offences. We will always investigate, and can arrange for you to have expert support and advice.”
Tallis will also be a registered sex offender indefinitely and was given a Sexual Harm Prevention Order (SHPO) – severely restricting his access to children, to last until further court order.