Titanic submarine missing: Ex-Royal Navy sub commander urges prayer for those missing on OceanGate Expeditions submersible 'Titan', including British billionaire Hamish Harding

The former UUP leader was speaking as rescue teams search for a British billionaire and four others who went missing while dropping 2.4 miles below the sea to visit the Titanic, which infamously sank on its maiden voyage from Belfast in 1912

The US Coast Guard is leading the search for the small craft, named Titan, which was reported overdue about 435 miles south of St John’s in Newfoundland, Canada, on Sunday evening.

British billionaire Hamish Harding, chairman of private plane firm Action Aviation, has been named as one of the people on board.

The Titan’s dive on Sunday is one of many that have been made to the wreck by OceanGate Expeditions since 2021.

“My thoughts and prayers are obviously with all the crew and passengers on board,” Mr Aiken told the News Letter. “It can't be a very pleasant experience.”

He joined the Royal Navy in 1980, commanding a nuclear-powered submarine and also serving on nuclear-armed vessels, before retiring in 2011.

He added: “They reckon it has about another 60 hours of oxygen - if the pressure hull is still intact.”

He said it is most likely that the submersible suffered some sort of power failure on its two hour controlled descent to see the Titanic.

The wreck of the Titanic lies some 3.8km under the water, he said.

This was much deeper than he would have normally travelled with the Royal Navy, although he declined to give any specifics, citing national security.

The vessel is not carrying a 'disabled sub beeper', which would allow it to be easily tracked, he said.

As a result, special sonar detectors are being dropped in the area to try and find the sub.

It is unlikely that a rescue vessel would be dispatched until they have located the vessel, he said.

Alternatively, it is possible they may send down a remote controlled vehicle to attach a cable - if they can find it.

The protocol is that those inside should be knocking on the hull every 15-30 mins to assist those searching for them.

"I am very concerned. No matter what you do it is an extraordinarily hostile environment. There is nothing natural about being in a submarine.

“And being in a submersible that is being run by a commercial operator - you don't have all the rules and regulations that the government would be operating to.

"I would probably be quite nervous about going down in something like that. It has previously had a fairly good safety record, but it only takes one thing to go wrong."

"The issue now is not just oxygen, but carbon dioxide and carbon monoxide levels also. Those are going to be significant problems."

He added: "Just pray for a miracle that they are found and that they can be rescued."

He added: "Submariners pray every time they go under the water - definitely."