The 44-year-old, who recently retired from the Royal Navy, said the extreme temperatures left crew “just collapsing everywhere, many at their work stations”.

The hunter killer submarine was only three hours from Fujairah in the United Arab Emirates on May 26, 2011, when the incident took place.

The boat had surfaced and Cdr Ramsey was on the bridge when engineers told him the air conditioning plants had “catastrophically” failed.

As he went below he was met by an “incredible blast of heat,” and the first casualties soon began to be taken ill.

Within hours many areas of the 275ft submarine had become makeshift sick bays, as 26 of the crew were taken casualty, he said.

“We had casualties in the control room, the engine room, the bridge, the wardroom, cabins, and the toilets and showers. It was absolutely terrifying, and I’m not afraid to say I was scared.

“Walking around the boat I saw true fear in my crew’s eyes.

“I saw genuine concern because we simply did not know how we were going to get through it.

“I felt like the world was against us.

“I was looking up and asking ‘when are you going to give me a break to gain the upper hand here?’

“People were crying, and it was all about survival.”

Cdr Ramsey said it was the first time such a malfunction had been reported on a vessel of this type – and the crew didn’t understand the exact cause of the problem. The heat meant the crew couldn’t reach the problem areas because the equipment was too hot to touch.

A decision was made that it was impossible to return to Fujairah with a “broken” nuclear submarine because of the political fallout. The crew opened two of the submarines hatches to release some of the heat and put some of the casualties outside, but with temperatures on the surface reaching 108F (42C) there was little respite.

The air conditioning system was used to cool sensitive equipment on board, which began to shut down.

A decision was made to dive to cooler water to reduce the heat.

“It was touch and go before we dived as to what might happen to us and the submarine,” he said.

“We couldn’t do anything. I could have radioed for help but it would have taken hours for anyone to reach us. In that time people would have died.

“We were alone in our steel tube. There really was no-one to call.”

Diving to a depth of more than 200 metres, the temperatures finally began to drop and within 24 hours systems had returned to normal and the crew were recovering. HMS Turbulent, based in Devonport, resumed her deployment.

Cdr Ramsey told the Plymouth Herald: “There’s not a day that goes by that I do not think about what happened. The pain of seeing my crew like that.

“But when I think back to that time I quickly remember how fantastic they all were in dealing with the situation.

“We recovered from it. They did exactly what they had to do, and looked after the team.”

Cdr Ramsey left the Royal Navy in March after 25 years’ service and said he had chosen to reveal the incident to highlight how “incredible” the secretive submarine service is.

He said: “The medical team was made up of one Petty Officer medic, another medic, and six or seven first-aiders and they did an unbelievable job under intense pressure.”

“That particular experience brought out some amazing actions from people who are rarely recognised, if ever, for what they do.”

HMS Turbulent, a Trafalgar Class submarine, was decommissioned in July 2012 at the end of a career of nearly 30 years.

A Royal Navy spokesman said the submarine’s nuclear reactor had never been at risk.

He said: “In 2011, a technical issue in HMS Turbulent resulted in a temporary rise in temperature on board the submarine.

“The problem, which caused no damage to the submarine or its reactor systems, was resolved by the crew after a few hours using standard operating procedures.

“A number of personnel who showed signs of heat related symptoms were treated by the submarine’s medical team.

“All recommendations resulting from the investigation into the incident have been fully implemented.”

Source – The Daily Telegraph