The woman who developed some 2500 personalities to survive her father's sexual abuse from the age of four clapped her hands to her face with joy as the elderly man was sentenced to 45 years in prison on Friday.

Jeni Haynes developed dissociative identity disorder (DID) after years of physical and mental abuse by her father in Sydney in the 1970s and 80s.

The sentence means Richard Haynes, 74, will almost certainly die in prison. Even with parole he won't be eligible for release until 2050, taking into account two years spent in custody since extradition from the UK in 2017.

Ms Haynes had previously been given permission by the court to call on about 30 of her 2500 alters she had developed to give evidence against him. Haynes, however, pleaded guilty at the 11th hour.