A report into a fire at an east London block of flats found a serious failure of the smoke ventilation system meant residents’ only escape route was smoke-logged, while timber decking may have contributed to its spread.

Two people needed hospital treatment after suffering the effects of smoke inhalation and another 38 adults and four children were treated at the scene after a fire ripped through the 19-storey New Providence Wharf development, near Canary Wharf, last month.

In a report released on Tuesday, the London Fire Brigade (LFB) said the building acted like a “broken chimney” after the smoke detectors failed to operate its automatic opening vent (AOV) and fire doors.

The fire on May 7 started in the fuse board in an eighth-floor flat and then spread out of an open balcony window up to floor 11, the report said.

It was said that the building’s timber decking on the balconies may have contributed to the fire’s spread externally.

The report read: “The point of origin for the fire has been determined as being the consumer unit (commonly known as a fuse board).

“Following the multi-agency scene examination, the fire will be recorded as being an accident, with no evidence whatsoever to indicate a deliberate act being found.

“The most probable cause of the fire has been determined as being an event within the consumer unit, which then resulted in its plastic enclosure/casing catching on fire and then in turn spreading to other combustible materials.”

It continued: “The smoke detectors should have operated the automatic opening vent (AOV) and cross corridor doors on the eighth floor. However, it is known that none of these systems actuated.

“This allowed smoke and the products of combustion to flow through the common parts of the eighth floor (and subsequently beyond) making it difficult/impossible for persons on this floor to escape safely, while increasing the challenges and risks for firefighting and search and rescue operations within the building.”

As the smoke began to spread, the report claims that the fire safety systems “did not perform as expected”.

The fire was able to travel up three floors after spreading through the open balcony door of the flat of origin, the report read, while the timber decking “supported the external flame spread up the outer face of the building”.

The LFB said the building’s aluminium composite material polyethylene (ACM PE) cladding, similar to that used on Grenfell Tower, “did not significantly contribute to the external spread of the fire”.

London Fire Brigade deputy commissioner Richard Mills said: ”The smoke ventilation system inside New Providence Wharf acted like a broken chimney leading to a potentially life-threatening situation.

“Had it not been for the exceptional actions of our firefighters and 999 control officers this could have had tragic consequences.

“Despite our response to this fire and drawing on the many lessons learned from the Grenfell Tower fire, in many cases we are sadly still not seeing a culture change in all those responsible for fire safety in high-rise buildings.

“The New Providence Wharf fire needs to be an urgent wake-up call to all building owners and managers.

“Look at the fire safety solutions inside your building and take action if they are not performing correctly. It is too late to wait for a fire to see if they work.”

A spokesman for building developer Ballymore said: “We are grateful to the fire service for their prompt reaction to the incident on May 7 which ensured that all residents were safely evacuated in a timely fashion.

“The safety of our residents is everything to us. Since the fire of May 7, we have inspected the fire prevention, detection and mitigation systems in all of our properties to ensure all are in working order.

“We will work closely with the fire service, our professional and scientific advisers, and our residents to assist with the ongoing investigation.

“Facade remediation works are under way at the New Providence Wharf building, at no cost to leaseholders.”