Debbie was nine-years-old and Laraine just seven when Patrick began to abuse them.
The abuse continued in secret for three years, between 1974 and 1978, until the girls moved house.
Patrick was jailed for 12 years in June this year at Woolwich Crown Court.
Debbie recalls: ‘One day Laraine had gone upstairs to play while Mum was at her cleaning job. I’d gone to the park two minutes away with friends. But I popped back briefly.
Laraine says: ‘I didn’t speak about the abuse for years because he made me feel ashamed. I almost drank myself to death to blot out what he’d done but Debbie and my family made me see sense just in time.
‘I know now none of it was my fault and I want to make up for all those lost years, start living again
‘Me and Debbie are living poof that justice can be done even years after. So if you’re living under the shadow we lived under, tell someone. Speak out. It will be hard, but you wont’ regret it.’
Although both sisters went on to marry and have children, the abuse continued to blight their lives and they suffered psychological trauma as a result of their experiences.