Three girls who were imprisoned by their mother in a house of indescribable filth for seven years may never recover from the ordeal, experts said last night.

The girls were shut away from the outside world, existing in almost complete darkness, playing only with mice and communicating in their own language.

When they were discovered, their home in a smart, upper middle-class suburb had no running water and was filled with waste and excrement a meter high. The floor was corroded by mice urine.

The case has stunned Austria, still reeling from the Natascha Kampusch kidnapping, and the authorities were struggling last night to explain how such a horror story could have gone unnoticed.

The girls’ ordeal was apparently sparked by their parents’ divorce, after which their mother, a 53-year-old lawyer, suffered a breakdown. But she won custody of the girls — then aged 7, 11 and 13 — and withdrew them from school, claiming that she would give them private tuition at home.

Her husband, a local judge in Linz, Upper Austria, named only as Andreas M, was not allowed to see them once, despite his claims for access reaching court nine times.

The girls, Viktoria, Katharina and Elisabeth, were rescued only when police broke into the house after a neighbour, who had reported his suspicions several times, threatened a local council official with a lawsuit.

Although that was in October 2005, and the three have been in a specialised therapy centre since, the scandal was only revealed at the weekend.

The mother is now being held in a special remand prison branch for the mentally unstable. She will appear in court in a few weeks on charges of grievous bodily harm and torture, and is facing between five months and five years in prison.

She had ensured that the blinds were constantly shut, and that all but one light bulb had been removed in the house. When they were released, the three victims had white skin and could not endure exposure to natural light.

Authorities are now under fire for failing to have intervened sooner, despite repeated complaints by neighbours in the well-to-do Poestlingberg.

The mother was said to have been summoned to court nine times during the seven years after complaints by the father and neighbours, but officials never found a reason to investigate the case more closely.

Waltraud Kubelka, a therapist who is now treating the three girls, said that their psycho-social and physical development was “catastrophic”.

“The oldest one is doing very badly and has no prospects of recovery. She was severely undernourished and practically anorexic after her release. The two younger ones will need years to come to terms with their horrific childhood.

“In the first weeks after their release they were hiding under a bench in the kitchen [in the therapy centre] because that was the darkest spot. They could not endure light . . . they had not felt sunlight or fresh air for years.”

It is believed that the children had contact only with their mother during the seven years of captivity and, as a consequence, developed an almost unintelligible language of their own, described as a “singing-like” form of German.

Even after a year of therapy the oldest daughter, Elisabeth, now 21, is said to be so disturbed that she stands only on one foot for long periods staring at the floor. She often bursts into tears.

She and her two sisters also reportedly finish all sentences with the word “but”.

But according to her carers, the youngest of the three, Viktoria, could soon be discharged from therapy to join her father, who now is in constant contact with his daughters.

A council official said that authorities had had no knowledge of the “truly catastrophic” conditions.

The mother’s legal training and knowledge of the law has reportedly enabled her to postpone the trial. The case will he heard in front of a court in Klagenfurt in the next weeks, as both she and her husband are well known in the legal community of Linz.

Natascha Kampusch was held for eight years by Wolfgang Priklopil, before escaping. Priklopil snatched her on her way to school when she was ten and kept her captive in a subterranean dungeon under his house near Vienna for eight years.

Professor Max Friedrich, a child psychiatrist who treated Ms Kampusch, said that the two cases should not be compared.

“This is entirely different, when the mother herself is the captor. It is tragic that the one person that commands full trust is misguided in that way. I do not envy their therapists.”