Protesters caused a scene after climbing onto the balcony of Boris Johnson's home, unfurling a banner and taking selfies, in protest at their perceived lack of father's rights in the UK.
'New Fathers 4 Justice' activist Bobby Smith, 33, from Stevenage, scaled the balcony of Mr Johnson's Islington home, on Colebrooke Row, dressed as Iron Man.
Speaking to getwestlondon from the balcony, he said: "They're sending up climbers to try and get us.
"We're doing a protest for father's rights. Boris wants to be Prime Minister and he's pushing himself out as more than just an MP, and more than a Mayor - he's a national figure.
"He's been London Mayor for eight years now and he's done nothing for fathers in the capital - he's done nothing for the poorer areas, not like Islington where we are now."
'I've been going through the family court and protesting for years'
Mr Smith, who has been denied access to his children since 2010, has climbed onto the roofs of many public buildings, alongside friend Martin Matthews from Great Bookham – including using a ladder to climb onto the roof of Buckingham Palace and scaling the home of House of Commons leader Chris Grayling, in a bid to get his voice heard.
He continued: "I split up with my children's mum eight years ago. Parenting was meant to be split 50/50 but she just stopped me seeing them.
"I've been going through the family court and protesting for years.
"Children are far more likely to commit crime or fall into drug addiction if they haven't got a dad. Boris has done eight years as Mayor and he's done nothing to promote change in family law to give a chance to hard-up fathers.
"We're talking about dads who want to see their children like me and my mate who's up here now."
'We want to stay for longer but they're trying to get us down'
Metropolitan Police have been at the scene since 10.40am.
A spokesperson for the police said: "We were called to Colebrooke Row to reports of protesters at a location.
"Four people were protesting and two had onto a balcony and unfurled a banner.
"Officers attended and there's no arrests at this time."
Police zone in on New Fathers 4 Justice protesters
Mr Smith was still on the balcony at 2pm and police were still at the scene.
He added: "There's load of police here, and an ambulance.
"There's just two of us on the balcony. We've been up here since half 10 and we're going to try and stay for longer but they're trying to get us down."
Mr Smith recently held a protest outside Boris Johnson’s London home but despite the Mayor of London being home he refused to speak to the protesting dad.
He posted something for him to read though his letterbox and warned him: 'I’ll just keep coming back till he’s ready to talk. He’ll give in before I do’.
Speaking ahead of the protest, Bobby said: “It’s no good sitting at home getting depressed and getting upset at how much you miss your kids. You need to stand up and not accept what has happened.
"There’s no equality for fathers in family law. I want nothing less than a legal presumption of equal contact for a child with their parents if they split up.”
He stood against David Cameron dressed as Elmo in the 2015 general election and is also standing again in the May Sheffield by-election.
Bobby 'Elmo' Smith leader of the Give Me Back Elmo party is also going to campaign for a "Shake it all about" option in the forthcoming referendum for those who can't decide whether they want to be in or out.
The protest outside Boris' home comes as part of a campaign by splinter groups New Fathers 4 Justice and Stop the War on Dads.
Neither group are associated with Matt O'Connor or Fathers4Justice UK.