Man hole covers were blown out and a 120 yard stretch of pavement along the north side of Queen Street was shattered by the blast.
But this was no Nazi bombing raid, it was later revealed that the explosion was due to a fault in the main electric cable buried beneath the pavement.
At around 7:30pm, lights in the office buildings on the opposite side of the street had began to flicker followed by a ‘deafening crash’ ten minutes later.
One eye witness working in the BBC building likened it to ‘a bomb going off’, while others claimed that the entire block shook for several seconds before all the lights went out.
Engineers ensured that broadcasting was not interrupted by supplying hand-held electric lamps.
Meanwhile, premises the length of the street were plunged into darkness, with the black-out lasting a number of hours.
Speaking to The Scotsman at the time, a caretaker of one of the buildings said: “I wondered what was happening to the lights here. They flickered in and out.
“Then came a noise from across the street like a fireworks thunder flash. I looked out of the window and saw smoke seeping out of the man-hole covers along the pavement on the opposite side. There was a bad smell of burning, then I saw one of the covers blow out.
“After that”, the man continued, “there was a bigger explosion, and the whole pavement, for about 120 yards, rocked and shook. It was like an earthquake.”
The massive explosion resulted in debris being thrown metres high into the air and across the street. Fragments of paving slabs hacked at the trees and even smashed windows on the opposite side of the street. A stationary bus located nearby also had some of its windows shattered.
Luckily, no one was injured during the explosion, including the handful of SMT bus drivers and conductors who had been stood next to their empty vehicles at the time of the incident.
For a couple of hours afterwards, utility officials and policemen assessed the damage and cordoned off the street. There were no further explosions.
Once the dust had settled, it was concluded that the explosion had been caused by a short circuit between one cable and another. A gas official was quoted as saying: “This might have created gas which travelled along the ducts, and found an outlet at the first man-hole cover, which was blown up,” he said. “Then the explosion along the route of the gas would naturally follow.”
There was a little panic at the nearby YMCA further up the street. The building was home to around 150 servicemen who were forced to navigate their way through the building in almost complete darkness.
Their only source of light was a single candle which was placed on the serving counter in the canteen.