Holborn fire caused by electrical fault, says fire brigade

The London Fire Brigade’s initial assessment of the blaze which raged underground in Holborn for 36 hours is that it was caused by an electrical fault.

The investigators believe the fault occurred in the Victorian tunnels running underneath the Kingsway, damaging an eight-inch gas main which ruptured and fuelled the fire. 

The initial findings made public on Thursday shift the focus back to London’s electricity distribution network, which is operated by UK Power Networks, following speculation that the blaze may have been deliberately set.

The fire service refuted earlier reports that the 1 April fire may have played a role in a high stakes jewellery heist in the area, saying that there was no sign of “deliberate firesetting”.

UKPN declined to comment on the initial findings of the fire service until the investigation was finished, but said in a statement that it managed to restore the majority of the 3,100 customers affected on the same day that power in the area was lost.

London Fire Brigade commissioner Ron Dobson said the “technically difficult fire” shows that “there are still hidden risks in London”.

UKPN is already undertaking extensive upgrades to the London network and are looking to invest around £80 million over the next eight years to ensure that safety procedures are robust. The investment includes plans to replace link boxes in central London over the coming years to curb the recent spate of “exploding pavements”. But the operator is also under pressure to comply with Ofgem’s mandatory requirements to keep costs low to protect consumers against rising bills.

In a statement, UKPN said of the Holborn fire: “This is the biggest emergency cable replacement project that we as a company have experienced to date – and its location beneath busy London streets brought extra challenges”.

At times restoring power to the area required over 400 engineers and more than 13km of new cabling, the network said. UKPN was also limited in the work it could do in the first two days following the fire because work was needed to isolate the gas network before sending engineers in to the area.

“We are currently resurfacing some major road excavations and doing everything we can to get the essential repairs completed as quickly as possible,” UKPN added.

A spokesman for the fire brigade told Utility Week there was no timeline for when final conclusions would be made, saying it will continue for “as long as it takes”.

UKPN said: “We want to reassure the public that our network is extremely safe, and that when there are problems we are identify and working to solve them as quickly as possible.”