Residents saw a “man on fire” in the street following a huge blast in Hackney’s Mare Street.

The victim who is in his 30s is thought to have been in a spray foam insulation van when the explosion ripped through the vehicle and the first floor of a nearby building - a shop with flats above it.

The van was completely gutted and the man – who had been inside it - was taken to hospital where he is fighting for his life in a critical condition.

Police stressed the incident was not terrorist related.

A police spokesman said: “At this early stage, it is believed that the fire was caused as a result of a works carried out near a generator inside a commercial property.

“As a matter of course, the Health and Safety Executive will be informed.”

Twitter user Liz Bisoux who had been on a bus said: “I thought it was just the van but as the bus went past it exploded and the whole shop was spewing flames.

“News is it was NOT terrorist related - but to be next to it when it exploded.. That was scary.”

Residents in Hackney told ITV News London they heard two loud bangs before seeing a man “on fire in the street”.

Four fire engines and around 20 fire fighters were called to the incident on Sunday afternoon just after midday, and had the blaze under control an hour and a half later.

Chris Hawkswell from the London Ambulance Service tweeted: “A number of resources are on way to a call given as a serious fire in Mare Street #Hackney, Emergency Planning Team standing by for update.”

The injured man, who was one of the workmen, was found at the scene suffering from serious burn injuries, was taken to an East London hospital by Air Ambulance.

A section of Mare Street, Paragon Lane and Loddiges Road were closed all day Sunday.