"I told him I was proud of him," says Lisa, a 21-year-old wages clerk. "I said that however long he managed to stay up there, I would be cheering him on and sending him my love.'
In the end, Mark, who staged his weekend protest with fellow Fathers 4 Justice campaigner from Devon Jolly Stanesby, stayed on the roof of Ms Harman's elegant period home in Herne Hill, South London, for 10 hours - an hour for every year that his own case wasn't resolved by the courts
When he climbed down on Sunday night, he was immediately arrested and detained by police, leaving Mr Stanesby perched precariously on the slates, stubbornly insisting he wouldn't descend until Mark had been released.
But then as Lisa points out, brushes with the law are nothing new to her 49-year-old father. During the decade he spent fighting for full access to his three daughters after his wife walked out and took them with her, the driving instructor faced 133 court appearances before 33 different judges, two stints in jail and went on a hunger strike.
The irony is that Mark's case is now resolved: Lisa, his eldest, now lives with him. So does his 17-year-old daughter. Another daughter, aged 15, lives nearby with her mother, but visits at least twice a week. He now has everything he fought for.
But he still donned Superman's leotard, tights and cape because while he is free to talk about the horrors he suffered at the hands of the British justice system, other fathers are not. Last year, the Lord Chancellor ruled that family court proceedings must remain secret and therefore, argue some, unaccountable.
"He hasn't forgotten what he went through," says Lisa. "He still has a lot of anger about it and he wants to do what he can to help other fathers in the same position."
If it seems strange that Mark is still angry about his own ordeal, then, as Lisa is quick to remind anyone who asks, until she was 16 - and legally able to choose for herself which parent she wanted to live with - she hardly knew her father at all.
Her life has been blighted by years of enforced separation from the father she clearly adores.
"Most people look back on their childhood and remember family days out at the seaside and birthday parties," she says. "My recollections are of Mum, sour-faced in a suit, heading off for yet another court appearance and endless interviews with social workers and child psychologists, all telling me that I didn't have to see my dad if I didn't want to."
Speaking to the Daily Mail on a previous occasion, Mark explained: "I missed so much. They took my daughter's childhood, her formative years, from me. Lisa is 21 now. I didn't see her between the ages of 10 and 16. An awful lot happens in a child's life in that time and I missed it all."
Lisa, too, has suffered. For years, she believed her father had abandoned her and couldn't understand why.
"There were times when I needed a father figure - for reassurance and advice. There just wasn't one there."
There are many gaps in their shared pasts, but one memory they both recall vividly is how, on the day Lisa returned home to her father, she walked into her bedroom and threw out all the toys and mementoes Mark had clung on to from her childhood, laughing nervously as she did so.
"It struck me just how much time had passed and how far she had moved on," said Mark. "We might be father and daughter, but we were starting again from scratch."
And despite her bravado as she threw away the dolls and teddies, Lisa admits that, in fact, her heart was breaking.
"When I walked into my old bedroom and saw it was exactly as I had left it all those years ago, I wanted to sob," she says.
"If I had ever doubted dad's love for me, here was the proof of just how unfailing it was. I didn't dare cry, because if I did I thought I might never stop."
With their comic book character outfits and off-the-wall publicity stunt protests, it would be all too easy to dismiss the Fathers 4 Justice phenomenon out of hand.
The group formed in 2002 and champions the reform of Britain's family law system and equal parenting rights for separated couples. It doesn't help, of course, that many of the group are legally prevented from speaking out and defending themselves.
And yet the personal story behind the group's latest desperate attempt to be heard is a salutary reminder that, when family decision-making is handed over to the State, families can be ripped apart.
As Mark pointed out, he didn't walk out of his children's lives; he was ordered out by the secretive family courts. And when he objected, insisting upon his right to see them, he found himself on the wrong side of the law.
He married a former driving school pupil in 1986 after a whirlwind romance and Lisa was born the following year, her younger sisters arriving in 1989 and 1991. Back then in those heady days of early fatherhood, he could never have imagined that he would one day end up on national television protesting on top of a minister's home.
"When Lisa was born, I was overwhelmed with love," he recalled. "I felt the luckiest man alive. Being a father quickly became what defined me."
He was, he said, a "hands-on" father and aside from regular rows about his "overbearing" mother-in-law, he thought his marriage was happy too.
His wife, however, clearly didn't agree. One day in November 1993, he returned home to find the four-bedroom family home in Plymouth ransacked. Most of the furniture and ornaments, as well as his wife and children, had gone.
"Later, she calmly explained that she no longer loved me, but that I could see the children whenever I wanted," he said. "She seemed so cold and uncaring - I didn't recognise her.
"I took the children home with me for a few hours and they spent the time crying, wanting to know when they could have their lives back. I didn't know what to say to them, because I was as bewildered as they were."
Over the next two months, Mark saw the girls nearly every day. Then, one day, two months after she had left, his wife asked if she could speak to him.
"She told me that she deeply regretted what she had done and asked if I would take her back," said Mark. "I refused. I was too hurt and angry.
"The following day, she changed her telephone number and from then on she refused even to answer the door to me, let alone let the children see me."
Life soon became a round of court appearances. At first, Mark was granted unrestricted access. But at the same time his wife applied to have his visits reduced, saying it was "confusing" for the girls to see him.
The family court agreed and cut his access from three times a week to once a week and finally to once a fortnight.
A year after they separated, the couple divorced. And that year, 1996, Mark returned to court in a bid to see more of his daughters. This time, he asked if they could come and live with him. His wife retaliated by saying that seeing him was unsettling the girls.
The judge's response was astonishing by any standards: he severed all Mark's rights of access.
"I was devastated," he said. "But I couldn't let that stop me being a father to them."
To show he cared, he stood on the street and waved to them when their mother drove them to school each morning. Then his ex-wife took out an injunction to stop him. Still he carried on waving.
"I thought the whole ridiculous business would be cleared up at the next court hearing," he said.
Instead, in November 1997, when he turned up at court, he was led away in handcuffs and jailed for four months. "They said my waving was tantamount to stalking my wife."
On his first night in jail, he shared a cell with a murderer. "I pined for my girls," he said. "When I got out, it took me another year to convince the courts that I should be allowed to see the girls at all."
Finally, five years after being separated from Lisa and her younger sisters, Mark was granted permission to see them under the supervision of social workers. At first, Lisa refused to come, convinced that he hadn't seen her for so long because he didn't love her.
"It hurt to think she didn't want to see me. But I hoped she would eventually come round."
Then, in January 2001, at a court hearing he hoped would increase his children's visits, he was sentenced to 10 months in Pentonville Prison for contempt of court. His crime? Driving past his wife's house, trying to catch a glimpse of the girls between the six unsupervised visits he was allowed each year. He went on hunger strike for two weeks.
"I stopped only when I realised that if I died, I would never see my girls again."
In the end, it was Lisa, not the courts, who resolved the situation. Over the years, she admits, she had given up on her father. "We thought he didn't love us any more," she says.
When her father was jailed, it served only to reinforce what she says were her mother's words: "I told you he was a bad man."
She says: "Mum's hate for dad seemed to run so deep, to keep her happy and get the social workers off my back, I told them all I never wanted to see him again. Turning love to hate seemed easier."
Over the years, she occasionally saw her father on TV. "One day, I caught him being interviewed along with some other dads who were also banned from seeing their children," she said.
"As I listened to them all talk about how all they wanted was to be allowed to be fathers to their own kids, I felt a pang for my own dad and what we'd lost."
On March 21, 2001, she telephoned her father out of the blue, saying that she and her youngest sister were at a bus stop with their bags packed and wanted to come and live with him.
"Seeing Lisa again for the first time in six years was incredible," recalled Mark, who has written a book, Family Court Hell, about his experiences.
"The last time we were together, she was a little girl. Right then I didn't know how to speak to, or even how look at, the young woman before me, in make-up and high heels with her 6ft boyfriend in tow. In the end, we just fell into one another's arms and sobbed."
Back home, he called a High Court emergency hotline. "I managed to speak to a decent, and very humane, judge. I told him everything, he spoke to the girls, and 10 minutes later faxed through a temporary residency order. In court, the following week, he cleared every previous court order and injunction that had been passed in the past 10 years relating to our case."
For Lisa, the reunion was hard at first. "The last time I'd seen my dad I was 10 and carried a skipping rope. Now I was 16, a young woman with a boyfriend in tow.
"Dad looked older and worn down by it all. It was a shock to see how he had aged."
Today, she and her father are closer than ever, while her relationship with her mother is strained. "As soon as the police release him, he's coming straight home," she says. "I can't wait to see him."
Yet there is lingering regret too, for herself and others who have to experience a similar ordeal.
"I wish to God that my parents had avoided the courts from day one and simply shared us, the children they created together," she says. "Instead, complete strangers were allowed to get involved in our lives to such an extent that everyone lost sight of the needs of us, the three people they were fighting over. All I ever wanted was to be allowed to love them both," she says.
Harriet Harman may have been justified in refusing to meet last weekend's uninvited house guests and listen to their complaints, but, in the end, Lisa's words say it all.
But then as Lisa points out, brushes with the law are nothing new to her 49-year-old father. During the decade he spent fighting for full access to his three daughters after his wife walked out and took them with her, the driving instructor faced 133 court appearances before 33 different judges, two stints in jail and went on a hunger strike.
The irony is that Mark's case is now resolved: Lisa, his eldest, now lives with him. So does his 17-year-old daughter. Another daughter, aged 15, lives nearby with her mother, but visits at least twice a week. He now has everything he fought for.
But he still donned Superman's leotard, tights and cape because while he is free to talk about the horrors he suffered at the hands of the British justice system, other fathers are not. Last year, the Lord Chancellor ruled that family court proceedings must remain secret and therefore, argue some, unaccountable.
"He hasn't forgotten what he went through," says Lisa. "He still has a lot of anger about it and he wants to do what he can to help other fathers in the same position."
If it seems strange that Mark is still angry about his own ordeal, then, as Lisa is quick to remind anyone who asks, until she was 16 - and legally able to choose for herself which parent she wanted to live with - she hardly knew her father at all.Her life has been blighted by years of enforced separation from the father she clearly adores.
"Most people look back on their childhood and remember family days out at the seaside and birthday parties," she says. "My recollections are of Mum, sour-faced in a suit, heading off for yet another court appearance and endless interviews with social workers and child psychologists, all telling me that I didn't have to see my dad if I didn't want to."
Speaking to the Daily Mail on a previous occasion, Mark explained: "I missed so much. They took my daughter's childhood, her formative years, from me. Lisa is 21 now. I didn't see her between the ages of 10 and 16. An awful lot happens in a child's life in that time and I missed it all."
Lisa, too, has suffered. For years, she believed her father had abandoned her and couldn't understand why.
"There were times when I needed a father figure - for reassurance and advice. There just wasn't one there."
There are many gaps in their shared pasts, but one memory they both recall vividly is how, on the day Lisa returned home to her father, she walked into her bedroom and threw out all the toys and mementoes Mark had clung on to from her childhood, laughing nervously as she did so.
"It struck me just how much time had passed and how far she had moved on," said Mark. "We might be father and daughter, but we were starting again from scratch."
And despite her bravado as she threw away the dolls and teddies, Lisa admits that, in fact, her heart was breaking.
"When I walked into my old bedroom and saw it was exactly as I had left it all those years ago, I wanted to sob," she says.
"If I had ever doubted dad's love for me, here was the proof of just how unfailing it was. I didn't dare cry, because if I did I thought I might never stop."
With their comic book character outfits and off-the-wall publicity stunt protests, it would be all too easy to dismiss the Fathers 4 Justice phenomenon out of hand.
The group formed in 2002 and champions the reform of Britain's family law system and equal parenting rights for separated couples. It doesn't help, of course, that many of the group are legally prevented from speaking out and defending themselves.
And yet the personal story behind the group's latest desperate attempt to be heard is a salutary reminder that, when family decision-making is handed over to the State, families can be ripped apart.
As Mark pointed out, he didn't walk out of his children's lives; he was ordered out by the secretive family courts. And when he objected, insisting upon his right to see them, he found himself on the wrong side of the law.
He married a former driving school pupil in 1986 after a whirlwind romance and Lisa was born the following year, her younger sisters arriving in 1989 and 1991. Back then in those heady days of early fatherhood, he could never have imagined that he would one day end up on national television protesting on top of a minister's home.
"When Lisa was born, I was overwhelmed with love," he recalled. "I felt the luckiest man alive. Being a father quickly became what defined me."
He was, he said, a "hands-on" father and aside from regular rows about his "overbearing" mother-in-law, he thought his marriage was happy too.
His wife, however, clearly didn't agree. One day in November 1993, he returned home to find the four-bedroom family home in Plymouth ransacked. Most of the furniture and ornaments, as well as his wife and children, had gone.
"Later, she calmly explained that she no longer loved me, but that I could see the children whenever I wanted," he said. "She seemed so cold and uncaring - I didn't recognise her.
"I took the children home with me for a few hours and they spent the time crying, wanting to know when they could have their lives back. I didn't know what to say to them, because I was as bewildered as they were."
Over the next two months, Mark saw the girls nearly every day. Then, one day, two months after she had left, his wife asked if she could speak to him.
"She told me that she deeply regretted what she had done and asked if I would take her back," said Mark. "I refused. I was too hurt and angry.
"The following day, she changed her telephone number and from then on she refused even to answer the door to me, let alone let the children see me."
Life soon became a round of court appearances. At first, Mark was granted unrestricted access. But at the same time his wife applied to have his visits reduced, saying it was "confusing" for the girls to see him.
The family court agreed and cut his access from three times a week to once a week and finally to once a fortnight.
A year after they separated, the couple divorced. And that year, 1996, Mark returned to court in a bid to see more of his daughters. This time, he asked if they could come and live with him. His wife retaliated by saying that seeing him was unsettling the girls.
The judge's response was astonishing by any standards: he severed all Mark's rights of access.
"I was devastated," he said. "But I couldn't let that stop me being a father to them."
To show he cared, he stood on the street and waved to them when their mother drove them to school each morning. Then his ex-wife took out an injunction to stop him. Still he carried on waving.
"I thought the whole ridiculous business would be cleared up at the next court hearing," he said.
Instead, in November 1997, when he turned up at court, he was led away in handcuffs and jailed for four months. "They said my waving was tantamount to stalking my wife."
On his first night in jail, he shared a cell with a murderer. "I pined for my girls," he said. "When I got out, it took me another year to convince the courts that I should be allowed to see the girls at all."
Finally, five years after being separated from Lisa and her younger sisters, Mark was granted permission to see them under the supervision of social workers. At first, Lisa refused to come, convinced that he hadn't seen her for so long because he didn't love her.
"It hurt to think she didn't want to see me. But I hoped she would eventually come round."
Then, in January 2001, at a court hearing he hoped would increase his children's visits, he was sentenced to 10 months in Pentonville Prison for contempt of court. His crime? Driving past his wife's house, trying to catch a glimpse of the girls between the six unsupervised visits he was allowed each year. He went on hunger strike for two weeks.
"I stopped only when I realised that if I died, I would never see my girls again."
In the end, it was Lisa, not the courts, who resolved the situation. Over the years, she admits, she had given up on her father. "We thought he didn't love us any more," she says.
When her father was jailed, it served only to reinforce what she says were her mother's words: "I told you he was a bad man."
She says: "Mum's hate for dad seemed to run so deep, to keep her happy and get the social workers off my back, I told them all I never wanted to see him again. Turning love to hate seemed easier."
Over the years, she occasionally saw her father on TV. "One day, I caught him being interviewed along with some other dads who were also banned from seeing their children," she said.
"As I listened to them all talk about how all they wanted was to be allowed to be fathers to their own kids, I felt a pang for my own dad and what we'd lost."
On March 21, 2001, she telephoned her father out of the blue, saying that she and her youngest sister were at a bus stop with their bags packed and wanted to come and live with him.
"Seeing Lisa again for the first time in six years was incredible," recalled Mark, who has written a book, Family Court Hell, about his experiences.
"The last time we were together, she was a little girl. Right then I didn't know how to speak to, or even how look at, the young woman before me, in make-up and high heels with her 6ft boyfriend in tow. In the end, we just fell into one another's arms and sobbed."
Back home, he called a High Court emergency hotline. "I managed to speak to a decent, and very humane, judge. I told him everything, he spoke to the girls, and 10 minutes later faxed through a temporary residency order. In court, the following week, he cleared every previous court order and injunction that had been passed in the past 10 years relating to our case."
For Lisa, the reunion was hard at first. "The last time I'd seen my dad I was 10 and carried a skipping rope. Now I was 16, a young woman with a boyfriend in tow.
"Dad looked older and worn down by it all. It was a shock to see how he had aged."
Today, she and her father are closer than ever, while her relationship with her mother is strained. "As soon as the police release him, he's coming straight home," she says. "I can't wait to see him."
Yet there is lingering regret too, for herself and others who have to experience a similar ordeal.
"I wish to God that my parents had avoided the courts from day one and simply shared us, the children they created together," she says. "Instead, complete strangers were allowed to get involved in our lives to such an extent that everyone lost sight of the needs of us, the three people they were fighting over. All I ever wanted was to be allowed to love them both," she says.
Harriet Harman may have been justified in refusing to meet last weekend's uninvited house guests and listen to their complaints, but, in the end, Lisa's words say it all.
Determined: Mr Stanesby says fathers are treated like 'walking wallets'
Fathers 4 Justice was shut down in January 2006 after extremist sympathisers were accused of plotting to kidnap Mr Blair's son Leo but was relaunched four months later when campaigners invaded the live broadcast of the National Lottery draw.
