A man who went on the missing Titanic submarine expedition has admitted "you sign a massive waiver that you could die on the trip" as fears grow for the passengers.
US and Canadian search teams are racing against the clock to find the tourist submarine with five people onboard as the rescue operation continued overnight.
Military planes, a submarine and sonar buoys have all been used to try and find the missing vessel as it is believed crew members had just days of oxygen left as of Monday evening.
The Titanic's wreck lies 435 miles south of St John's Newfoundland, with the recuse mission being run from Boston, Massachusetts.
Hamish Harding and father and son Shahzada Dawood, 48, and his son Sulaiman Dawood, 19, were on board the submarine, according to Action Aviation, a company for which Mr Harding serves as chairman.
The initial group of tourists in 2021 paid $100,000 to $150,000 apiece to go on the trip.
Mike Reiss, an American television writer and producer, told BBC Breakfast he did three separate dives including one to the Titanic and said tourists are required to sign a waiver acknowledging they could die on the trip before boarding.
The writer said when he boarded the boat which takes passengers to the Titanic, a list is given to passengers which reveals they might not return from the trip.
Mr Reiss said: "To get on the boat that takes you to the Titanic, you sign a massive wavier that you could die on the trip.
"On the list, they mention death three times on page one and it's never far from your mind. As I was getting on the submarine, this could be the end.
"Nobody who was in this situation was caught off-guard. You all know what you're getting into, it's exploration, it's not a vacation, and it's not thrill-seeking, it's not like skydiving, these are explorers and travellers who want to see something."
Mr Reiss revealed the ship is not "shoddy" but as it's new technology there is always a risk something could go wrong.
He added: "This is not say it's a shoddy ship, it's just all new technology and they're learning it as they go along. You have to remember the early days of the space program, or the early days aviation, where you make a lot of mistakes on the way to figuring out what you're doing."
Mike revealed he's "not optimistic" the vessel will be found as he believes it is at the bottom of the ocean so will be incredibly difficult to access and bring it back up.
He said: "I'm not optimistic because I just know the logistics of it and I know how vast the ocean is and how very tiny this craft is.
"It's a beautifully designed craft. I can't disparage it, it's meant to go down further than any other vessel than anything else. If it's down at the bottom, I don't know how anyone is going to be able to access it and bring it back up.
"There is hope it's at, or near, the surface. The phrase we keep hearing is we lost communication. I did three separate dives, one to the Titanic and two more off the coast of New York, and every time they lost communication."
