Cereal Killer cafe damaged in Shoreditch anti-gentrification protest
Activists opposed to what they claim is the gentrification of parts of east London threw paint and daubed the word "scum" on a business selling cereal.
The owners of the Cereal Killer Cafe said staff were "absolutely terrified" when protesters targeted the shop on Saturday night.
Police said the disorder, which spread into Brick Lane, began at about 20:00 BST and lasted for several hours.
One man was arrested on suspicion of causing criminal damage.
Alan Keery, who runs the Cereal Killer cafe with his twin brother Gary, told the Evening Standard newspaper: "There were children there - they were terrified.
"The staff were absolutely terrified. It was an angry mob throwing paint at the windows. They had torches and pigs' heads."
He added: "We're being targeted as the poster boys of gentrification and that's not our fault."
One witness told the BBC: "We don't know why they did it but they were wearing Cameron masks. They've written Class War on their banners.
"And later threw paint on the cafe. The staff and employees barricaded themselves inside."
'Mob won't win'
The brothers from Belfast, who opened the cafe in December 2014, were forced to defend their prices after a Channel 4 interviewer asked whether local people could afford £3.20 for a bowl of cereal.
On Sunday they tweeted: "The mob won't win, wearing masks with pitch forks and torches, it's 2015. #hatecrime"
The pre-planned demonstration was advertised on Facebook, with organisers saying: "We don't want luxury flats that no-one can afford, we want genuinely affordable housing.
"We don't want pop-up gin bars or brioche buns - we want community.
"Soon this City will be an unrecognisable, bland, yuppie infested wasteland with no room for normal (and not so normal) people like us.
"London is our home and worth defending against this onslaught of dog-eat-dog economics.
"Working class people are being forced out of our homes but we won't go out without a fight."