Piper Alpha: How the world's worst offshore disaster happened
The Piper Alpha disaster claimed the lives of 167 men on July 6, 1988.
On July 6, 1988, 167 men lost their lives in the worst offshore disaster in history.
By the time the sun dawned the next morning, the Piper Alpha oil platform was a ruin and the North Sea would never be the same.
In the months and years which followed it emerged that a series of mistakes and coincidences were responsible for the events of that night.
They began when a pressure safety valve was removed from one of two pipes used to export gas condensate from Piper Alpha - Pump A and Pump B - during routine maintenance.
The engineer carrying out the work did not have time to replace the valve on Pump A before the end of his shift and sealed it off with a metal plate.
At 9.45pm, Pump B failed and the crew - unaware Pump A was dangerously unsafe - activated it, causing a high-pressure leak which quickly ignited.

A series of smaller blasts followed the initial explosion but Piper Alpha's firefighting system failed to activate and rescue boats including the Tharos, a large firefighting rig stationed nearby, were mobilised.
However, the Piper Alpha's crew were unable to reach lifeboat stations or the helideck and the intensity of the flames prevented the Tharos from reaching the platform.
At 10.20pm, a gas line linked to Piper Alpha ruptured, causing a second large explosion. It swept outwards from the platform, killing two crewman on the deck of a nearby rescue boat and the six Piper Alpha workers they had saved from the water.
Men leapt 175ft from the platform into the freezing sea to escape the flames. Among them was scaffolder Joe Meanan.
"When the pipe fractured and the huge fireball engulfed the platform it was just a scramble," he said.
"That's when I thought I was maybe near the end. You had the sense that something really catastrophic had happened but didn't really know because you were in the middle of it.
"I ran over to the north side of the platform. I took my lifejacket off and took a few steps and threw myself off as hard as I could. I felt nothing until I hit the water.
"I knew I had to get back to the surface. You could feel the heat and the back of you. I found a lifeboat that had been blown off the platform so I managed to swim over to that and climb into it."

A second gas line ruptured at 10.50pm, forcing the Tharos to retreat.
Many of the men left alive aboard Piper Alpha took shelter in the fireproof accommodation block and awaited a rescue which would not come.
At 11.18pm the gas line connecting Piper Alpha to the Claymore platform ruptured and the facility began to buckle under the intense heat.
Less than 30 minutes later the accommodation block collapsed into the sea. None of the 80 men inside survived.
By 12.30am all that remained of Piper Alpha was a single module.
Of the 226 men aboard Piper Alpha on the morning of July 6, just 61 survived the disaster. It took three weeks to extinguish the blaze which consumed the platform.

Naomi Reid father Bob Ballantyne survived Piper Alpha and became an outspoken critic of North Sea safety standards. He died in 2004, aged 61.
"I've grown up with Piper Alpha, it's always been such a huge part of my life," she said.
"I've had to live with it as well, it's something I've always known. It changed my father.
"He was aways fighting for safety and better conditions offshore before Piper Alpha. It wasn't until after he died that I understood what happened that night.
"I don't think we should ever forget about Piper Alpha. It's part of me."
Download: The STV News app is Scotland's favourite and is available for iPhone from the App store and for Android from Google Play. Download it today and continue to enjoy STV News wherever you are.