A North East university lecturer - who was the first British diver to see the Titanic wreck - has said it is a "dangerous" and "hostile" place to be.
Dik Barton, a lecturer at the University of Sunderland, made 22 dives to the wreck to recover artefacts when he was head of operations with RMS Titanic Inc, a US firm which salvaged the site. On Wednesday, he told ITV's Good Morning Britain he has "100%" felt in danger during previous expeditions to the wreck site.
A rescue mission is under way to try to reach a submersible with five people on board which went missing near the Titanic wreck since Sunday.
"It's a very, very dangerous, hostile place to be," Dik said. "There's a local ebb and current of water which moves around, it's not consistent. The strength of the submersible is relatively limited."
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He added: "The thrusters are quite strong but, at the end of the day, you have to conserve your power because it's your life support system and navigation system." Mr Barton told the programme he is friends with Paul-Henry Nargeolet, reported to be on board the missing vessel, and referred to him as "PH".
"PH is an extremely capable submersible operator pilot," he said. "He is a deep water explorationist, he's been down (to) the Titanic 37 times.
"I've worked with him extensively, I have enormous respect for him and his ability, and, quite frankly, if there's anybody I'd ever want to be in a position, God forbid, in this circumstance then it would be PH. He will be certainly doing all he possibly can to make sure everyone is calm and collected and waiting for recovery."
Mr Barton said there is no way of accessing the submersible on the sea bed and that for passengers and crew to be rescued the vessel has to be recovered back to the surface.
It has been reported that noises were detected from the search area of the missing deep-sea vessel as those on board face a dwindling supply of oxygen. The submersible, named Titan, lost communication with tour operators on Sunday while about 435 miles south of St John's, Newfoundland, during a voyage to the shipwreck off the coast of Canada.
Titan has five people on board, including British billionaire Hamish Harding, Shahzada Dawood, his son Suleman and OceanGate's chief executive and founder Stockton Rush, as well as French submersible pilot Paul-Henry Nargeolet.
The US Coast Guard on Wednesday morning said: "Canadian P-3 aircraft detected underwater noises in the search area. As a result, ROV (remote operating vehicles) operations were relocated in an attempt to explore the origin of the noises. Those ROV searches have yielded negative results but continue. Additionally, the data from the P-3 aircraft has been shared with our U.S. Navy experts for further analysis which will be considered in future search plans."
