Dungeon daughter taught her incest children maths and grammar in their cellar prison

Christoph Herbst told a Channel 4 documentary that Elisabeth has not decided whether to seek compensation from her father for his years of abuse.

The family are also undecided about changing their identity.

In his first British TV interview, the lawyer told how Elisabeth's five-year-old son, Felix, recently saw a thunderstorm for the first time.

He said the family live a "more or less regular life" in the Austrian hospital they have lived in since the authorities discovered that Josef Fritzl had locked up his secret family in the cellar.

He said: "They rise at about six or seven in the morning. Then they have breakfast together.

"They get the breakfast from the hospital... Then they sit together at a large table and talk, discuss and make jokes.

"Then everybody does their own thing. They play on the computer, they read books, do some drawings, whatever they want ... It's very amazing to watch the family because they behave like a normal family."

He said of the children: "Elisabeth tried to educate the children in the dungeon. They had lessons, they learned grammar, they learned the language, mathematics.

"So they have been raised very well, they are very well behaved....I think Elisabeth tried to give them a structure and a good life under the circumstances in the dungeon."

He told The Secrets of the Austrian Cellar that Elisabeth gets on "very well" with the three children who were taken away from her to live upstairs with their father.

But it was "difficult" for the children whose normal lives have been disrupted by the media attention.

The Secrets of the Austrian Cellar is broadcast on Channel 4 tomorrow at 9pm.