London, Nov 27: British Prime Minister Gordon Brown has vowed to investigate why it took so long for local authorities to uncover shocking incest case of a man, dubbed the ''British Josef Fritzl'', who made his daughters pregnant 19 times.

The 56-year-old Sheffield businessman, who called himself the "gaffer" around the family home, repeatedly raped his two daughters.

As a result, the girls, whose identities have been covered, gave birth to nine of his grandchildren, two of whom died at birth, and suffered ten miscarriages.

The man, who cannot be named in order to protect his victims'' identities, began sexually abusing his daughters in the early 1980s. If they refused their father''s advances, they were badly beaten, punched, kicked and held up to a gas fire.

The case has disturbing parallels with that of Austria''s Josef Fritzl, who fathered seven children with the daughter he locked in a dungeon for 24 years.

Prime Minister Gordon Brown expressed his revulsion at the man''s crimes at Prime Minister''s Questions: "The whole country will be outraged by those unspeakable events that have been reported as happening in Sheffield and in other parts of the country and will be utterly appalled by the news of the systemic abuse of two sisters by their father over such a long period.”

"People will want to know how such abuse could go on for so long without the authorities and the wider public services discovering it and taking action. If there is a change to be made in the system and the system has failed we will change the system,” the Telegraph quoted him, as saying.

Sentencing the man at Sheffield Crown Court, the judge, Alan Goldsack QC said: "I can say that in nearly 40 years of dealing with criminal cases and 14 as a family judge the combination of aggravating circumstances here is the worst I have come across.

"I have little doubt that many members of the public hearing the facts of this case will consider either you should never be released from prison or only when you are old and infirm. I agree with that view."

He added: "As a result of this case questions will inevitably be asked about what professionals, social and medical workers have been doing for the last 20 years."

In a statement, Jayne Ludlum, the director of Sheffield''s Children and Young People''s Specialist Services, said: "Due to the seriousness of this case, an independent review has already been launched which will look into the circumstances surrounding the case and the contact that agencies had with the victims to investigate what could have been done better and highlight any lessons to be learned." (ANI)