It is not clear why the group, that included activists, academics and public sector workers on strike over cuts to their pensions, were initially arrested, but one witness, who arrived as the group were being kettled outside CLR James Library in Dalston Lane, said it seemed unprovoked and unnecessarily violent.
The police, accompanied by around six dogs, were accused of pushing two woman, believed to be in their 50s, to the ground before arresting them for no apparent reason.
The activist, who did not want to be named, said: “I did not see what happened before, but I could see no reason for the kettle, the violence or the arrests.”
He said those detained in the kettle were arrested one at a time before being put into police vans.
The Metropolitan Police said a Section 60 was in place based on intelligence authorising stop and search measures in the area, but gave no further information.
Around 100 activists, friends and family of those arrested demonstrated outside Stoke Newington Police Station tonight over the detentions.
Officers at the station failed to shed any light on the nature of the arrests or who they were detaining.
Earlier Hackney’s dustmen and street cleaners got the national strike under way at the crack-of-dawn as up to 2m public sector workers took industrial action across the country in a bid to save their pensions.
The government wants to increase contributions made by staff by three per cent while forcing them to work a year longer from 2020 for the same payout following retirement.
However, dozens of staff could be seen crossing picket lines at Homerton Hospital, the Town Hall and the Technology and Learning Centre, which houses the library, museum and Education Trust, while street cleaners could be seen at work on Mare Street prompting an angry reaction by a striking teacher.
Karen Lynn, Unison’s education convenor for Hackney, said: “Some people don’t to lose a days pay and some are young and think pensions are so far away that they’re not important to them at the moment.”
Hackney Council said waste services and leisure centres, which are contracted out, would be unaffected by the strike, but all libraries, except Stamford Hill, would be closed and Hackney Homes would only be carrying out emergency repairs.
The majority of schools are also closed due to the action, however, Mossbourne Academy said it was closed for routine staff training while Petchy Academy would be open to three year groups.
Civilian police staff were reportedly also striking along with some PCSOs.
Ms Lynn said: “I hope the government will listen. No one chooses to strike, but people do feel strongly. It’s our money we pay into our pensions. The government has no right to take it. It’s like a savings bond. The average female pension is only £4,000 a year so we can’t afford to have it taken away.”
Paramedics and ambulance drivers kept warm outside their station on Homerton High Street as they huddled round a bin-fire encouraged by cars tooting their horns in support.
However, attempts to prevent a laundry van crossing the picket line at nearby Homerton Hospital failed as a private security guard intervened upsetting one nurse who said non-essential deliveries should be turned back.
Ruth Woolhouse, Unison’s shop steward for the child and mental health department of the hospital, said the threat of cuts to people’s pensions had boosted recruitment to the union in recent months, but there was still work to do.
She said: “We had redundancies in April and our managers have told us there will be more next April as they need to make a four per cent cut in efficiency savings every year, but we still have the same amount of work to do.”
Back at the waste depot Jim, the Unison shop steward, warned of further strikes if the government did not listen.
He said: “We had a strike two years ago but this is more heartfelt, it’s a popular strike. The union has put forward reasonable options, but they [the government] are just saying no, but I think they [the negotiations] will come to a reasonable conclusion [otherwise] it could happen again in the new year.”
But George Osborne criticised the unions for taking strike action while talks were still ongoing.
A Hackney spokeswoman advised residents with non-urgent enquiries to contact the Council on another day, but would be keeping services in place for its most ‘vulnerable’ residents.