A man who fathered nine children by raping his two daughters over many years has been jailed for life with a minimum term of 19-and-a half years.
The 56-year-old from Sheffield was sentenced to a life term for each of the 25 rapes he had admitted.
The attacks led to 19 pregnancies, Sheffield Crown Court heard.
The daughters said in a statement: "His detention in prison brings us only the knowledge that he cannot physically touch us again."
The defendant refused to leave his prison cell to attend the sentencing.
Nine of the children were born, two of whom died on the day of their birth. The other 10 pregnancies were miscarried or aborted.
The daughters' statement through South Yorkshire Police added: "The suffering he caused will continue for many years and we must now concentrate our thoughts on finding the strength to rebuild our lives."
The father moved the family from village to village in rural locations to keep them isolated and to avoid detection.
Sheffield Crown Court was told that he "took pleasure" in knowing the harm he was doing to his daughters.
Judge Alan Goldsack QC said: "Questions will inevitably be asked about what professionals, social and medical workers, have been doing for the last 20 years."
When either one of his victims tried to end the sexual abuse, he threatened to kill them and their children
Nicholas Campbell QC
Jayne Ludlam, director of children's and young people's services at Sheffield City Council, said the abuse was revealed to social workers in June.
Ms Ludlam said: "This is one of the most harrowing cases we have had to deal with and to say we are shocked to find this level of abuse being perpetrated by this person is an understatement.
"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 the agencies had with the victims."
James Baird, representing the defendant, said: "It must be inconceivable to those who have listened to this case that these offences have been carried out, in this day and age in a so-called civilised society, over such a long time and with such consequences, without them being reported or investigated."
The court heard that the sexual abuse started when the two sisters were prepubescent but that they only realised the other was being abused when they became pregnant some years later.
The court heard that on a number of occasions doctors advised the women to stop having children by the same father.
Nicholas Campbell QC said: "The defendant played Russian roulette as to whether there would be complications in the pregnancies and with the health of his daughters."
The defendant threatened his daughters with a "real hiding" if they refused to have sex with him.
Mr Campbell said: "All the defendant's children spoke of his domination over their family life. He was tall and strongly built."
"All the family were frightened of him. When they heard his car pulling up outside the house, the children and their mother ran to their respective rooms.
"His younger daughter told of the frightening habit her father had of putting her head next to the flames of their gas fire and that when she struggled to get away on certain occasions she burnt her eyes."
On one occasion, the women called Childline and asked for a guarantee that they could keep their children, but when one was not offered they ended the call.
Mr Campbell said: "When either one of his victims tried to end the sexual abuse, he threatened to kill them and their children, and when they threatened to tell police, he said they would not be believed.
"All the time, when the sisters were challenged about the paternity of their children, they would cover it up.
"They started taking the pill. He said they should not be taking it and, just as they felt unable to avoid his sexual abuse, they obeyed.
"They spoke of his pleasure at fathering their children whilst at the same time they had fears for the welfare of these children and how they would cope."
Lib Dem leader and Sheffield Hallam MP, Nick Clegg, said: "All our thoughts are now with the victims of this most abhorrent crime, who must be given the time and privacy to rebuild their lives."
His fellow Sheffield Brightside MP and former Home Secretary David Blunkett said it was difficult to determine who, outside of the family, could have been expected to take steps to intervene.
He said: "Those who at least made an effort to do something should not be the ones who are pinpointed - it is those who did not who should examine their conscience."
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.