He liked to be known as "The Gaffer" and used violence, bullying and emotional control to terrorise his daughters over 30 years of systematic sexual abuse which resulted in 18 pregnancies.

His control over the family, along with his self-employed status in the building trade, made it easy for him to move home quickly whenever there were awkward questions, to keep the children off school whenever they showed signs of injury and, crucially, to keep them silent.

The details of his abuse were first disclosed in November 2008 during his trial at Sheffield crown court. The case drew chilling comparisons with that of the Austrian Josef Fritzl, who imprisoned his daughter underground for 24 years and fathered her seven children.

But while Fritzl kept his daughter prisoner, the Sheffield father isolated and controlled his family using violence and bullying. Despite several cries for help that went unheeded, his daughters only broke their silence in 2008.

The man, 56, from Sheffield, "took pleasure" in assaulting the girls, the court heard, and the violent attacks would stop only while the children were pregnant.

The assaults took place against a backdrop of alcohol and domestic abuse – their mother, who knew about the rapes but was too terrified to do anything, escaped him to live in refuges on several occasions and finally fled the home in 1992, leaving her children behind.

His son, who was physically but not sexually abused, told police his father was a "Jekyll and Hyde" character who would "turn with a click of his fingers". He told the BBC: "Everyone recognised the sound of his car and when we heard it, it was like a dash to our rooms and hide."

The son said he once witnessed his father kicking and punching his elder sister, "beating her to a pulp". He felt powerless to do anything about it, he said, and managed to escape the family home when he was 15.

His father began physically abusing his daughters when they were toddlers: the rapes began when they were eight and 10. He managed to keep it hidden from the other child – each only realised the other was being abused when they fell pregnant years later.

In the beginning, he raped them every day, then two to three times a week. When they were pregnant, he would carry on, forcing each woman to babysit the children while he assaulted her sister. He told them their children would be taken away if they told anyone about the abuse, and threatened to kill them and their children.

Once the children were born, the sisters had another reason to stay quiet. At one point one daughter rang ChildLine for help, but hung up after she was not given a guarantee that the children would not be placed in care.

The rapes continued until 2008, until the women sought help, and resulted in him fathering nine children, two of whom died the day they were born. The sisters also suffered several miscarriages and terminations between them.

His self-employed status, running his own business in the building trade, made it easy for him to uproot at short notice and the family moved every six months or so, living in isolated villages in South Yorkshire and Lincolnshire,

The man, who is divorced, was given 25 life sentences in November 2008 after pleading guilty to 25 counts of rape committed from the 1980s up to the present day.

He is not mentally ill, Sheffield crown court was told; his abuse was "just satisfying his urges".

He remains unrepentant, refusing to attend court to hear his sentence and last year appealing against his sentence.

While on remand the man wrote a letter to a relative: "We were all getting on well before this came out," he wrote. "What went wrong? My daughters have got something out of this – kids – what have I got?"