Harriet Harman was forced to move out of her home today after two Fathers 4 Justice protesters climbed onto her roof to demand a meeting.
Ms Harman, who is Minister for Women and Equality, said it was not fair to waste police time or disturb her neighbours so she was going to stay elsewhere.
In a statement she said: "At about 7am Fathers 4 Justice climbed on the roof of my house.
"We are going to move out and stay somewhere else. I don't think it's fair for police resources to be tied up outside my house by this demonstration."
The two protesters - Mark Harris and Jolly Stanesby, from south Devon - were dressed as superheroes "Captain Conception" and "Cash Gordon".
A spokesman for the group said the demonstration on the roof of Ms Harman's south London home was intended as an "early Father's Day strike" against the Government over fathers' access to their children.
The campaigners said they intended to remain at the property until the Minister read Mark Harris's book, 'Family Court Hell'.
Fathers 4 Justice founder Matt O'Connor said: "Harriet Harman and the Government have refused all dialogue with F4J for the past two years.
"We are now resuming a full-scale campaign of direct action against the Government, its ministers and the judiciary. F4J is now the last line in the defence of fatherhood."
The protesters said police had told them there were two residents inside the house, thought to be Mrs Harman and her husband Labour Party treasurer Jack Dromey.
Mr Harris said: "All we did was push open the gate which wasn't even locked, put a ladder up and climbed up.
"In this time of heightened terror alerts I can't believe Harriet Harman has such lax security.
"My house is more secure than this."
He added: "We are not here to cause any damage or trouble. It's all very peaceful and we won't threaten anyone."
A Scotland Yard spokeswoman said: "We were alerted at 8.51am to reports of two males on the roof of a residential address in Herne Hill.
"Officers are currently in attendance at the location and are speaking to the
Speaking at the scene Fathers 4 Justice spokesman Darryl Westell said he did not know how long the men would be on the roof, adding: "As long as possible. Probably until Harriet Harman herself comes out and speaks to us.
"Harriet Harman is one of the proponents of family destruction in this country.
"Just two weeks ago in the IVF debate Labour removed the need for a father.
"It's another nail in the coffin for fathers. Harriet Harman should be ashamed of herself.
"Gordon Brown once said nothing means more than being a father. If that's the case the law needs to change.
"If you are a dad in this country and the mum isn't interested in you having contact with the child on a regular basis the law is not interested.
"This isn't about individual men. It's about the right in law for fathers to see their children."
Asked whether the stunt was the best way to get attention for their cause, he said: "You (the media) wouldn't be here if it wasn't for these brave guys getting up on Harriet Harman's roof.
"I don't care about Harriet Harman. I don't care about ruining her Sunday. I don't care if they have broken the law."
This is the latest in a long line of high-profile Fathers 4 Justice protests.
The most notorious incident involved activist Guy Harrison throwing a flour bomb at former prime minister Tony Blair in the House of Commons in May 2004.
Mr Blair was unhurt, but speaker Michael Martin immediately suspended the sitting halfway through Prime Minister's Questions.
Fathers 4 Justice was shut down in January 2006 after extremist sympathisers were accused of plotting to kidnap Mr Blair's son Leo.
But it was relaunched four months later when campaigners invaded the live broadcast of the National Lottery draw.
Members have previously raised awareness of their cause by scaling high-profile buildings, including Buckingham Palace, dressed as superheroes.