Housing campaigners have voiced concerns that fire safety measures could lead to a loss of social homes at the site of a former women’s prison.
Extra staircases may be required for tower blocks being built as part of a major scheme to convert the Holloway prison into housing.
Islington Council last year approved Peabody housing association’s plan for 955 homes, including 415 social homes, and a park at the historic women’s jail.
The site, which once housed suffragettes on hunger strike and where Ruth Ellis was the last woman in the UK to be hanged, was sold for £82m in 2016.
Since the plan was approved last year, the Mayor of London said all planning applications for buildings taller than 30 metres must have a second staircase – a response to the Grenfell Tower disaster.
The government is expected to weigh in on the issue soon after it held a consultation on making second staircases mandatory in high towers.
Campaign group Community Plan for Holloway want reassurances that the safety measures would not mean a loss of social homes in two of the tower blocks.
Richard Hope said the group welcomes the second staircase requirement, but design revisions could “impact the shape of the plans” and take up the space of a single bedroom “or more”.
“The downside might be instead of having two-bedroom apartments, it might have one-bedroom apartments,” he added.
“We do not know the detail. We are hoping for the best.”
He said developers might decide to build more private homes to cover the extra building costs.
The issue was discussed at the council’s housing scrutiny committee.
Resident member Rose McDonald said: “We do not want to see the number of homes reduced.”
Peabody’s chairman Lord Kerslake told the committee that the first phase of work has already been registered with building control and spades are due in the ground “imminently”.
There is no legal requirement to build a second staircase to the blocks with social homes, he explained.
“Nevertheless, we have still decided to provide a second staircase to those blocks.”
A third tower over 30 metres high will be built in phase three and Lord Kerslake said it “will be looked at in the broadest sense for compliance with any new building regulations in effect”.
A Peabody spokeswoman said: “Safety is our top priority and all buildings over 30 metres at Holloway Park, measured in accordance with fire safety regulations, will include a second staircase.
“We’re now reviewing the design of these buildings and will minimise the impact this has on the size of homes and number of bedrooms as much as possible.“
Peabody is due to discuss the prison site at a council housing scrutiny meeting on 6 June.