Floral tributes were being left at the former petrol station in Swain’s Lane where a man was tragically killed in an explosion as police investigated the cause of the blast.

Ham & High: A petrol tank being removed from the building site the day of the explosion (Pic: Ozzie Yelken)A petrol tank being removed from the building site the day of the explosion (Pic: Ozzie Yelken) (Image: Archant)

Police were guarding the site on the corner of Highgate West Hill this morning as mourners left flowers after the explosion at 2pm yesterday.

Emergency services involving the police, fire services, and ambulance services scrambled to the scene in the aftermath.

A man in his 50’s, believed to be a subcontractor, was air-lifted to hospital and later died from his injuries.

Eyewitnesses described a “huge bang” which shook buildings in the street and set off car alarms around the site.

Ham & High: The aftermath of the explosion in Swain's Lane Picture: Kenneth TharpThe aftermath of the explosion in Swain's Lane Picture: Kenneth Tharp (Image: Archant)

Nobel House developers began demolishing the parade of shops and filling station last month.

It is expected that an investigation will examine whether correct procedures were followed for removing hazardous materials including fuel tanks and pipes from the filling station.

Camden Council said it would assist with the investigation and that as part of the planning permission conditions had been imposed on developers to ensure it was suitable for redevelopment.

Councillor Jonathan Simpson, cabinet member for community safety, said: We were deeply saddened to hear a man had died following an explosion on a privately managed building site at Swain’s Lane yesterday. Our thoughts are with all who knew him at this difficult time.

“The Health and Safety Executive are responsible for investigating what happened in this case. We will assist them as required and await the investigation’s outcome.”

Camden Council had required developers to carry out a full report on the site and what measures should be taken to make it safe for redevelopment.

The report, by Chelmer Consultancy Services, had identified fuel tanks, filler pipes and an oil interceptor on site and said that remedial work was required.

Their document stated “the site is not considered to pose an unacceptable risk to ground workers, provided that appropriate health and safety protocols are employed.”

Ozan Yelken, who works at Bistro Laz opposite, said: “I heard a big bang and thought it was a wall collapsing at first. I went outside and couldn’t see anything. Then I saw two people run into the construction site.

“I don’t know what caused this explosion.”

Suresh Patel, of Megs News opposite the building site, added: “It was a huge explosion.”

Dr John M Slater, chairman of the Swain’s Lane Residents and Neighbourhood Watch Association, said: “Residents are saddened by the death of the subcontractor and their thoughts are with his family.

“A garage occupied this site, many years ago, and the petrol tanks have remained buried. Residents have expressed, over a long period, concerns about possible contamination.

The 1920’s shopping parade was sold by the Earl of Listowel to Nobel House last year who are replacing the row of shops with residential flats and retail units.

Cllr Sian Berry, who represents Highgate said: “I’m shocked that this has happened. It’s horrible someone died. We hardly ever hear about construction site deaths and for one to happen in the heart of Highgate you have to feel really sorry for everyone working there and the man’s family.”

A spokesman for the HSE said: “Now these injuries have tragically proven fatal the police has a duty under the law to investigate this. The HSE is assisting the police in their enquiries.”

Nobel House said in a statement: “In a statement the directors of Nobel House Properties, said: “It is with great sadness that a man died in a tragic accident at our site on Swains Lane last Thursday afternoon.

“The demolition works and removal of the tanks was being undertaken by a specialist company, Material Movements Ltd, who were instructed by our main contractor and had been used by them previously and are well respected in the industry.

“Whilst the accident is being investigated, we know nothing more at this stage.

“Our thoughts are with the family and relatives at this time.”

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