Leopold Etz, the head of Lower Austria's murder commission, was the first officer to set eyes on the frightened, ashen-faced Fritzl boys, Stefan, 18, and Felix, five, who had spent their whole lives underground. "They both looked terrified and were terribly pale," he said. "The two boys were taken upstairs from the underground bunker and appeared overawed by the daylight they had never experienced before.

"The real world was completely alien to them," Mr Etz said, "Later on that evening, we had to drive them to hospital. We had to drive very slowly with them because they cringed at every car light and every bump. It was as if we had just landed on the Moon," he added.

The boys were said to be able to communicate quite well in German, although their use of language and speech was far from normal. "They did not speak much in the bunker," said Dr Berthold Kepplinger, the director of the clinic where they are being cared for.

"Most of the speech they heard came from a television that was on in the cellar most of the time," he added. Both were said to be at risk from vitamin D deficiency resulting from lack of sunlight.

Kerstin Fritzl, 19, the first child to result from Elisabeth's enforced incest with her father, was still in hospital yesterday where doctors said she was "fighting for her life" from the affects of an illness induced by incest. "She is in a coma and her condition has only marginally improved," a spokesman said.

Doctors and psychologists are caring for all members of the Fritzl family, apart from Josef, at a hospital in Amstetten. Elisabeth Fritzl is reported to look much older than her 42 years. Her hair has turned completely white and her speech had also been affected by her 24 years in captivity.

Psychologists were almost unanimous in their view that the ordeal suffered by Elisabeth, Kerstin, Stefan and Felix would mark them indefinitely. "The four will never be able to live normal lives. I am afraid it is too late for that," Bernd Prosser, a clinical psychologist told Austrian television. However, the reunion of the Fritzl family members was described by doctors as an "astonishing success". The older children found it relatively easy to make contact. Only five-year-old Felix was said to have clung anxiously to his mother's legs.

Elisabeth Fritzl and her mother, Rosemarie, had not seen each other since 1984. The mother was apparently convinced that her daughter had run away to join a sect. Doctors who witnessed the reunion said the two burst into tears and hugged each other for a long time.