An initial investigation into a serious fire at a Mitcham warehouse this morning has indicated the blaze was caused accidentally.

Streatham Road was closed in both directions after about 50 firefighters were called to the blaze at the FedEx (Federal Express) warehouse in Mitcham Industrial Estate, St James Road, at 4.45am.

After the fire was put out at about 7.30am a Fire Investigation Unit examined the cause of the accident and, this afternoon (4pm), a London Fire Brigade spokesman confirmed an initial examination found the cause to be accidental.

The exact cause of the fire was not disclosed but arson has been ruled out.

At the scene, John Lalor, manager at Paddington station fire crew, said two potentially explosive propane gas cylinders had to be cooled down and removed from the warehouse.

He said: "The initial crews were greeted by quite a fierce fire. They did really well to contain it to just the damage on the first floor.

"A security guard was here to allow them to enter from the ground floor.

"They used breathing apparatus and a thermal imaging camera and, as is usual in these situations, they had to crawl on their bellies while they navigated the building.

The road closure meant the 127 and 201 buses had to be diverted, but Streatham Road reopened at about 8am.

Did you see what happened? Did you take pictures? Call Omar on 020 8722 6335, tweet @OmarOakes or email: ooakes@london.newsquest.co.uk.