A specialist fire and rescue service, Havering's only unit dedicated to floods, car accidents and chemical spills has been ordered to cease operations by London Mayor Boris Johnson.
The cutting of the Hornchurch-based engine comes as part of £28.8 million citywide cuts to the London Fire Service.
The announcement was made on Monday after Mr Johnson overruled both the London Assembly and the London Fire and Emergency Planning Authority (LFEPA), which both voted against the cuts.
Joining the Assembly and LFEPA in opposition was the Fire Brigades Union (FBU), which has also voiced concerns over safety if the unit closes.
Across the capital, the cuts will see ten stations, 14 engines and at least 550 jobs go – and the changes must be implemented by September 16.
The initial number of stations to close was set at 12 but New Cross and Clapham were saved when the Fire Commissioner Ron Dobson revised the proposals.
Ben Sprung, FBU Regional Officer for London, said: "Any cuts to the fire service, whether it is fire engines or firefighters, pose a danger to public safety.
"The area that the Hornchurch unit serves has large amounts of fast-moving traffic on very busy roads and anyone who lives or travels through the area is at risk."
James Cleverly, chair of the London Fire and Emergency Planning Authority, said: "The commissioner is confident that sufficient cover will be provided to Havering by fire rescue units based at East Ham and Bethnal Green fire stations.
Boris Johnson said: "Ensuring that London's fire service is financially stable and keeping Londoners safe are top priorities.
"I am perplexed as to why the Fire Authority has felt it necessary to lead the service into an increasingly precarious position by not facing up to its fiscal responsibilities and by rejecting the sound professional judgement of the Fire Commissioner, a firefighter with more than 20 years of experience.
"As a result, I have issued a direction which requires the authority to adopt the London Safety Plan as proposed by the Commissioner on July 18 so that there is a balanced Fire Authority budget for 2014-15 and so that compulsory redundancies can be avoided.
"We need to move forward to face the challenges of 21st-century firefighting."
A London Fire Brigade spokesman said: "As part of the consultation process on our proposals for the future of the capital's fire service, we have listened to Londoners and looked at what savings can be made from our wider operational fleet as a whole and have examined the utilisation of our fire rescue units.
"The £6 million that would be released as a result of reducing our fire rescue unit fleet from 16 to 14 would enable us to keep two fire stations open, Clapham and New Cross, and two further fire engines.
"On average, fire rescue units spend 4 per cent of their operational time at incidents.
"Hornchurch is one of the four quietest stations and because we plan our emergency cover on a pan-London basis, other stations equipped with fire rescue units, such as East Ham and Bethnal Green, will still provide sufficient coverage to this area."
Without the Hornchurch engine, Havering's nearest specialist rescue units will be at East Ham and Bethnal Green.
