The lower tunnel of the deep shelter used as an Army transit centre, showing the aftermath of an intense fire within the deep underground facility. Senior fire officers and a fire crew, wearing breathing apparatus (BA), inspect part of the tunnel and the fire area. The nature of the combustible construction within the tunnel assisted in the growth and intensity of the fire. Both the depth and length of the two tunnels, some 1200 feet (365 metres) in length, made this an extremely difficult fire to fight.