Ian John Watkins, 73, of Woodlands, Bexhill, appeared at Kingston Crown Court on Monday (May 9), said the Crown Prosecution Service (CPS).
The CPS said he was convicted of nine historic counts of indecent assault against the girl and two historic counts of indecency with a child.
He was sent to prison for three years.
He had pleaded not guilty to all charges at an earlier court hearing, the CPS added.
The spokesman for the CPS added that Watkins was also given a 10-year restraining order banning him from contacting the victim directly or indirectly.
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