The London Fire Brigade (LFB) has revealed the cause of a huge fire at an industrial estate which destroyed units at the site.

Around 125 firefighters rushed to Ferry Lane in Rainham on June 20 to find an industrial unit ablaze.

It took almost five hours to control and a warehouse containing multiple industrial units was destroyed by fire. 

A 25-metre cordon had to be put in place as a precaution but there were no reports of any injuries.

The LFB has been investigating the cause of the fire and today (July 11) confirmed its findings.

"The cause of the fire was accidental, but the ignition source is undetermined," an LFB spokesperson said.

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A common reason for an "undetermined" cause is that the building structure is unsafe hindering the investigation, the spokesperson added.

Another common reason is not enough evidence to confirm a sole cause, they added.

On June 20, the LFB received almost 30 calls about the blaze having been told just after 1.15pm.

It was put out just before 6pm that day.