Doctors treating two daughters who were made pregnant 19 times by their abusive father failed repeatedly to follow professional guidelines on alerting the authorities to suspected rape.

Failings by the authorities in the case of a Sheffield father who forced his daughters to bear him nine children included breaches of medical codes and ignoring the recommendations of an inquiry into a recent incest case.

Gordon Brown spoke of the nation's outrage yesterday as he vowed that lessons would be learnt from the “unspeakable” abuse.

The Prime Minister said that any necessary changes would be made to the system as a result of the case, in which the 56-year-old businessman — known in court as Mr X to protect his daughters' identities — received 25 life sentences for rape.

His crimes against his daughters, committed over at least 25 years, have been compared with those of the Austrian rapist Josef Fritzl.

“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,” Mr Brown told MPs at Prime Minister's Questions.

“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.”

The Times has learnt that the repeated failure of health professionals, social workers and the police to intervene, breached a key recommendation of an official review four years ago into an case of rape and incest with disturbing similarities.

In 2003 a man from Swindon was jailed for 15 years after fathering six children by his eldest daughter during 30 years of abuse.

The inquiry into the failure to halt the abuse found serious failings in the way the agencies worked together and shared information despite growing suspicion about the origin of the children. It recommended that in future cases of suspected rape within the family, agencies should prepare a family tree and a chronology of significant events.

Details of the case involving the sisters from Sheffield show that, after one of them had given birth, doctors began questioning whether the baby's father was also the father of the newborn's mother. They failed to follow procedures set out by the General Medical Council dictating that authorities should be alerted in such cases.

Doctors in hospitals in South Yorkshire and Lincolnshire who became aware of the family's history of recurrent genetic disorders also advised the sisters on separate occasions not to have more offspring with the man fathering the children. Two of the nine children died within hours of being born because of conditions caused by genetic defects. Nicholas Campbell, QC, for the prosecution, told Sheffield Crown Court this week: “Someone in the hospital asked whether the father of the child was her own father. The daughter was terrified and she denied it.

“Her mother was present and she collapsed on the floor crying out, 'no, it can't be true', but at no time did she ask her daughter questions about the identity of her child's father.”

A Serious Case Review is being carried out into why social services in Sheffield and Lincolnshire, and the police in both counties, failed to protect the girls despite warnings.

Lincolnshire Social Services admitted yesterday shortcomings in the work of their staff, which allowed the abuse to continue for 25 years.

Peter Duxbury, director of children's services at Lincolnshire County Council, said that the way information was shared between the authorities had changed since the family lived there and that nowadays the case “would have been dealt with in a different way”.

The role of schools and teachers will also be examined as part of the case review. On one occasion in 1988, burn marks on the face of one of the girls were spotted at their school but were put down to bullying.

The other daughter suffered a broken arm but stayed off lessons to conceal her injuries.

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