Veteran campaigner Bobby Smith, who lives in the town, was joined by Sharon Chesterman, also from Stevenage, and Surrey man Martin Matthews for the afternoon demo.
They ended their protest, which saw them dressed in ‘Anonymous’ masks and Father Christmas outfits, just before 6pm after scaling the roof of the Danesgate court complex at around 1.30pm.
The group said in a statement: “This is part of a campaign by splinter group ‘New Fathers 4 Justice’ and Stop the War on Dads.
“Christmas is a very emotional time when you are unable to see your children or grandchildren.
“Many people will go through the formalities of buying presents for children and grandchildren and putting them under the tree, hoping above hope that they will see them.
“More than four million children did not see one of their parents on Christmas Day due to family breakdown.
“Biased and flawed family law gives no automatic right of access to biological fathers or grandparents.”
Bobby Smith stood against Prime Minister David Cameron at last year’s general election to highlight the campaign, and has also been involved in high-profile rooftop protests in London.
New Fathers 4 Justice campaigns for equal rights for fathers in divorce and separation proceedings and reform of the family courts.
A spokesman said: “No parent who is fit and willing should ever be denied their right to share equally in the lives of their own children.
“We use direct action and protests to highlight the injustice fathers face in the present family court system.
“We want nothing less than a legal presumption of equal contact for a child with their parents if they split up, and the abolition of the deeply controversial, undemocratic secret court system that still exists within the ‘family’ division despite 40 years of inequality and protest.”
You can find out more about their aims at www.newfathers4justice.co.uk