A masked gang attacked an office building before a meeting to promote multi-cultural Britain.

Witnesses – including borough councillors – told the Post that around 20 far-right activists charged Crown House in Linton Road, Barking, before smashing windows and doors with rocks.

They were heard repeatedly chanting “EDL, EDL” – English Defence League – then pounded the entrance with their boots, fists and a ramming log.

A young woman was taken to hospital with a hand injury last Thursday after shielding herself from flying glass.

Kelvin Williams, of Unite Against Facism, who was in the building at the time, said: “They started smashing frontage windows with rocks.

“They were wearing hoodies and covering their faces. This is a street strategy of thugs.”

Abbey ward Cllr Laila Butt, who was also at the meeting, said: “I was shocked to see racism in my home town after 20 years of living in Barking, for me to experience it at that level, I was stunned.

“One of the women had her hand split open. She said they had rammed a log through the door.”

The meeting was attended by representatives from a number of organisations including UAF, Labour councillors and the National Union of Teachers.

Meeting organiser, Mayesbrook ward Cllr George Barratt, added: “It is very disturbing. Here we are living in Barking and Dagenham, which is a very peaceful place.”

EDL leader Tommy Robinson said on Friday he was not aware of the attack, but indicated it may have stemmed from members’ anger at the borough’s “leftist” agenda.

He said: “It sounds like people’s frustration boiled over.

“I would condemn the attack if there was any violence. But I can completely understand their frustration. People are so fed up with the leftist agenda.”

Crown House agents Glennys said the damage would cost hundreds of pounds to repair.

Tenants at Crown House include Barking and Dagenham Council’s marketing team, Sternberg Reed solicitors and HM Revenue and Customs’ Valuation Office Agency.

Detectives were this week trying to trace the group believed to have fled on trains from Barking Station after 7pm.

A Met spokeswoman said: “Prior to police arrival, the group made off in the direction of Barking Station. An investigation is under way.”

The EDL is a far-right protest group founded in 2009, which has organised UK street marches including protests against a Muslim community centre and mosque in Green Lane, Dagenham, earlier this year.

Anyone with information is asked to call police on 020 8984 1212 or Crimestoppers on 0800 555 111.