A fire in Greenwich’s Blackwall tunnel which caused traffic chaos this morning is believed to have been caused by an electrical fault.

Six fire engines and 40 firefighters were called to the blaze which was in a small part of the cable tunnel near the Northern Approach at 4.06am.

The fire began after testing by on-site engineers.

The tunnel was closed at 4am after a fire alarm was activated but reopened at around 7.30am.

The blaze was brought under control by crews from East Greenwich, Poplar, Millwall and Deptford fire station at 6.03am.

A spokesperson for London Fire Brigade: “Six fire engines and around 40 firefighters tackled a fire in the Blackwall tunnel in Greenwich.

“A small part of the cable tunnel in the Northern Approach of the Blackwall tunnel was damaged by the fire following testing by on site engineers.

“There were no reports of injuries.

“The fire is believed to have been accidental caused by an electrical fault.

“The Brigade was called at 4.06am and the fire was under control at 6.03am.

“Fire crews from East Greenwich, Poplar, Millwall and Deptford fire stations attended the scene.”