Herts Fire and Rescue have said the cause of a major fire was “accidental”, as businesses await structural engineers.

The fire at a large commercial building yesterday in Langley Wharf, Railway Terrace, Kings Langley, was fully extinguished by around 12.50am this morning (January 31).

Firefighters then returned to assess the building at around 5am, logging the cause as accidental and confirming there was no further fire risk.

Watford Observer: The fire, in Langley Wharf.The fire, in Langley Wharf. (Image: Contribution)

Businesses immediately around where the fire initially broke will apparently have to await the findings of structural engineers before returning to their units, while others can already return.

Although Herts Fire and Rescue did not leave the scene until the early hours of the morning, they began scaling down their operation, which saw 12 fire engines called, by around 5pm.

There are multiple businesses operating within the larger Langley Wharf building, and it is not yet confirmed where the fire began, however it appears to have been a "warehouse" unit.

The East of England Ambulance Service confirmed that no-one required medical treatment.

Railway Terrace was shut in both directions to allow emergency services to respond to the fire yesterday.