A father who repeatedly raped his two daughters for nearly 30 years told the children the abuse would never stop.

They finally broke the silence this year, but only after he had fathered nine of their children.

After nearly three decades of abuse, the 56-year-old father was sentenced Tuesday to life in prison with the possibility of parole in about 20 years after pleading guilty last month to rape and assault. During years of incestuous abuse, the man fathered nine children from his two daughters.

"In nearly 40 years of dealing with criminal cases ... (this) is the worst I have come across," judge Alan Goldsack said in his ruling at Sheffield Crown Court in northern England.

The case carries echoes of the case of Josef Fritzl — an Austrian man who confessed to imprisoning his daughter in a cellar for 24 years and fathering her seven children.

Prosecutor Nicholas Campbell said the daughters were raped regularly from an early age. If they resisted, they would be punched, kicked or held to the flames of a gas fire.

The father was furious when he first found out his eldest daughter was pregnant, but nevertheless he refused to let the girls take birth control pills, Campbell said.

The girls' only reprieve came after they had just given birth or when they were too badly hurt by his abuse, Campbell said.

In one incident, the father held a knife to his eldest daughter's throat and told her: "It's never going to end," according to Campbell.

The father made his elder daughter pregnant seven times, fathering two children by her. She bore two other children but they died the day they were born. He made his younger daughter pregnant 12 times; Campbell said she has five surviving children.

The family reportedly moved house around small and isolated villages in northern England.

Campbell said the man held the family — including his wife and son — under a reign of terror. The daughters reported the abuse earlier this year to social workers but it was unclear how the incest could remain secret for so long.

Although the sisters were kept out of school when they bore marks of their abuse, Campbell said that even neighbors had commented on the family's growing numbers.

Goldsack, the judge, noted that they made frequent visits to the hospital.

"Questions will inevitably be asked about what professionals, social and medical workers, have been doing for the last 20 years," Goldsack said. Those questions were likely to dominate the front pages in Britain, where attention has lately focused on problems with the country's child welfare services. The British tabloid press was already up in arms over the death of a toddler who was allowed to suffer months of excruciating abuse at the hands of carers despite regular visits to his home by social workers, doctors, and police.

Authorities said they had already launched an investigation.

The sisters said their abuse would stay with them "for many years."

"We must now concentrate our thoughts on finding the strength to rebuild our lives," they said in a statement read out by South Yorkshire Police Chief Superintendent Simon Torr.

The girls' mother left her husband in the early 1990s. Prosecutors said the woman, who was reportedly divorced from her husband, was not facing charges. Britain's Daily Mail newspaper said the brother of the sisters tried to alert police to the incest in 1997, but that the sisters refused to cooperate and nothing happened.

During the hearing Tuesday, Campbell quoted him as saying that his father had a "Jekyll and Hyde personality" and that he lost his temper at the drop of a hat.

"All the family were frightened of him," Campbell said. "The defendant also ensured that his family were kept isolated and that there were very few visitors to the home," he said. "Rather than having baby sitters, the children recall being locked in their rooms when their mother and father went out."

Reporting restrictions bar the publication of most identifying details about the family.