Plans for new tall residential buildings in London will need to incorporate a second staircase in order to be signed off, the mayor of London has announced according to InsideHousing.

An update on the Greater London Authority’s (GLA) planning pages said that planned buildings over 30 metres tall will “need to be designed to provide two staircases before they are referred to us at Stage 2 for the mayor’s decision”.

Stage 2 is the latter stage of approval by City Hall, for major planning applications that are required to be referred up to the body by local councils in London.

The decision could require the redesign of dozens of applications currently progressing through the planning system in London to either add a second staircase or reduce the height threshold. 

It follows the launch of a consultation by central government in December, which proposed introducing a requirement for a second staircase.

The call follows pressure from fire safety campaigners, architects and firefighters’ bodies in the aftermath of the Grenfell Tower fire. 

Speaking before the announcement from the GLA, large developing housing associations told Inside Housing they were already reviewing projects in their pipelines. 

Research carried out after the fire by academics at McGill University in Montreal assessed building codes in 30 countries and found that only England, Wales and South Korea have no requirement for a second staircase in residential buildings of any height. 

This can be a major problem during a fire, because it means the firefighting operation and evacuation are forced into the same space. 

When firefighters access a flat on fire, they typically run hoses from the floor below, which means they are required to prop open fire doors separating the staircase from the communal landings. 

The staircase can then quickly become compromised with smoke, risking injury to any residents who need to flee. 

The mayor’s update said the requirement will apply at 30 metres, the same height threshold proposed for national regulations, despite the National Fire Chiefs Council (NFCC) calling for a lower threshold of 18 metres. 

The national consultation said it would adopt “a very short transition period with new developments being encouraged to prepare for this change now”. 

“In light of this – and given the requirements of [the] London Plan… that all developments should achieve the highest standards of fire safety – we are clear that, with immediate effect, all planning applications which involve residential buildings over 30 metres in height will need to be designed to provide two staircases before they are referred to us at Stage 2 for the mayor’s decision,” it said. 

“The GLA’s planning team is working with the boroughs to progress schemes which are currently in the pipeline to ensure they include two staircases where necessary before any Stage 2 referral. 

“We are all working hard to look at feasible options to secure this and try to meet key timescales, particularly given the impact planning delays may have on affordable housing grant funding.”

Grant funding usually requires developments to complete by a set date to avoid it being paid back to government – although this has been waived in the past when providers have missed deadlines. 

Speaking before the latest announcement, a spokesperson for Clarion Housing Group, the UK’s largest social landlord and one of the largest developers in London, said it was “currently reviewing” existing schemes.

“We are engaging with the government’s consultation on second staircases, which has our full support,” it said. “We are currently reviewing each relevant project to identify what amends, if any, are needed and how these can be implemented. We will redesign any projects which have yet to start and will seek fresh approval for their plans as necessary.

“There needs to be greater clarity around the requirements of any forthcoming legislation as at present the consultation is ambiguous and could lead to significant delays to a number of projects in our programme.

“We are reviewing the implications on any projects that have started on site under the current published building regulations.”

Peabody, another large developer of affordable housing mostly based in London, added that it “can’t complete any necessary redesigns until the building regulations guidance is revised”.

A spokesperson said: “We are reviewing the potential impact of the government consultation on the schemes we currently have in development but can’t complete any necessary redesigns until the building regulations guidance is revised.   

“We will also be interested to see how proposals and planning permissions based on current regulations are honoured in advance of any new guidance coming into effect.” 

Be First, the development arm of the London Borough of Barking and Dagenham, said it would introduce an 18-metre threshold for a second staircase in all of its proposed schemes.