Aboriginal activist Robert Bropho had his jail sentence doubled aftera ruling by the Court of Appeal today.
Bropho, 78, was found guilty in the District Court last year on five of seven charges of having unlawful carnal knowledge of a girl under 13 years.
The offences occurred in Guildford and Eden Hill between March 1990 and July 1991.
He was jailed for a total of three years for these crimes but the Director of Public Prosecutions has now successfully appealed against the sentence.
Today the Court of Appeal increased the total sentence to six years which means that Bropho will be eligible for parole after four years from the date he was sentenced in February 2008.
The Court said that Bropho was a predator upon a young, vulnerable girl and the sex offences were committed over a period of months.
At the same time the Court of Appeal dismissed Bropho's claim that he was wrongly convicted of the charges.
PERTH ROY GIBSON