Details have emerged about the fatal 18 June expedition, with the New York Times reporting how the divers prepared for the expected 12-hour trip.

Father and son Shahzada and Suleman Dawood, British billionaire Hamish Harding, French sub pilot Paul-Henri Nargeolet and Stockton Rush, the chief executive of the company OceanGate that owned the submersible, were killed when the vessel suffered a catastrophic implosion.

The Dawoods almost didn't make the expedition after their initial flight from Toronto to St John's in Newfoundland was cancelled and their rebooked flight was delayed.

The prominent Pakistani family had met Mr Rush and his wife in February in a cafe near Waterloo station, where they discussed the design and safety of the submersible.

In the days before their deaths, the divers attended safety meetings and presentations on board the submersible's mothership, the Polar Prince, a former Canadian Coast Guard icebreaker that was built in 1959.

The five people killed were told to eat a "low-residue diet" the day before the dive, and to not drink coffee that morning.

They were also asked to load their favourite songs on their phone to play on a Bluetooth speaker, but Mr Rush insisted no country music be included.

Divers were told to wear thick socks and a hat, as it would get colder the deeper the submersible went.

Christine Dawood, the wife and mother of Shahzada and Suleman Dawood, said they were given OceanGate flight suits, waterproof trousers, an orange waterproof jacket, steel-toed boots, life vests and helmets.

The five were also warned to avoid getting their feet wet from condensation that would form on the floor.

During the dive, the victims would have only seen bioluminescent sea creatures through the 21-inch porthole on the way down to the Titanic wreckage, as the floodlights were turned off until the submersible reached the seabed to save battery.

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Mr Rush, the pilot, usually sat at the back of the submersible away from the porthole. The others sat with their backs to the curved walls.

The submersible typically descended at about 25 metres per minute, according to the New York Times, so those on board would feel no sense of motion.

The US newspaper also reported that more Titan missions were aborted than accomplished.

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The first four OceanGate dives this year did not reach the Titanic.

There were extensive safety concerns, with several submersible experts flagging issues.

During a Titan mission in 2021, divers had to move their weight from side to side to dislodge weights attached to the submersible which would result in the vessel coming back to the surface when a dive was aborted.

Several investigations into the implosion are underway after pieces of debris were found about 487 metres from the Titanic five days after the vessel lost contact.