Staff at the Stranglands Lane plant had to be evacuated from part of the site after the fire broke out at about 5am.

Crews from Pontefract, Castleford and Knottingley tackled the fire, believed to have been sparked by a faulty underground cable.
It was declared a major incident by the fire service as firefighters had to work in a confined area where they faced exposure to up to 33,000 volts of power.

On-site water drenchers flooded the area and brought the fire under control before a group of about 12 firefighters entered the basement with carbon dioxide fire extinguishers.

Keith Brook, watch manager at Castleford station, said: "It was necessary to form a co-ordinated plan of action. We could not just send officers down there spraying water in the dark with electricity cables everywhere.

"It was a matter of fighting the fire back to a point where it was safe enough to send people in to attack it properly."

A spokesman for site owners Scottish and Southern Energy said an investigation into the cause of the fire, which posed no danger to the public, had been launched and that power supply to customers was not affected.