Titanic submarine implosion: Loss of Oceangate 'Titan' with all five on board will resonate with Belfast more than most, says ex-sub commander

They had been trying to visit the wreck of the Titanic almost three miles under water just off the coast of Canada.

Wreckage has been around the search site and the US Navy heard a sound akin to an implosion on Sunday.

The Titanic was built at Harland and Wolff in Belfast, but struck an iceberg on its maiden voyage in 1912 and sank, with the loss of some 1,500 lives.

"It is obvious that the US Navy picked something up on Sunday, which was probably the implosion," said Mr Aiken, a former Royal Navy nuclear submarine commander, and a former leader of the UUP.

He suggests the US did not immediately volunteer the information to avoid disclosing their capabilities.

It is "fairly obvious" that the Titan imploded on the way down on its dive on Sunday, because that is when its communications also failed, he added.

"Regrettably that is when the five of them lost their lives. The only thing you can say is that implosions at that depth means that death would be instantaneous, so that is one small comfort, but it won't be much for the family and relatives."

The tragedy may resonate with Belfast more keenly than most other cities, he said, bearing in mind its long association with the Titanic tragedy itself.

"We are and always have been very closely linked with the sea. We are a maritime country. Haarland and Wolff built many of the ships in the world and we do feel that affinity for those that have lost their lives at sea. So our concerns are out there with them."

He added: "I think in this particular tragedy, the fact that the sub was diving on the Titanic, those are the kind of things that will resonate with people.

"We go and visit the Titanic museum in Belfast and we see the initial dives that went down there. People [in Belfast] have probably got a broader understanding of what the conditions

are like down there.

"The Titanic was a tragedy and more than anything else was a combination of bad seamanship and being pushed to go too fast by the company that owned it.

"By contrast the Titan was cutting edge technology - but technology that wasn't proven and wasn't particularly well tested.

"It is a tragedy but there are many questions to be asked about Titan and why it was allowed to do what it did."

Steve served in the Royal Navy Submarine Service for 26 years and has spent more than a few calendar years under water.

"You understand a lot of what was going on," he said of the search for survivors.

Asked if he often thought of the dangers when he was under water, he said: "You cannot talk to any submariner who has spent any significant time at sea and not had those thoughts."

However, what reassured him in the navy was "very good training, good maintenance and sensible operating".