OceanGate said it has "suspended all exploration and commercial operations" following the implosion of the vehicle last month while on a voyage to the undersea wreckage of the Titanic off the coast of Canada.

The company had planned two trips to the ruins for June 2024, its website showed.

All five people on board were killed, including UK citizens Hamish Harding and father and son Shahzada and Suleman Dawood, alongside OceanGate Expeditions' chief executive Stockton Rush and the submersible's pilot, French national Paul-Henri Nargeolet.

Presumed human remains were recovered from the wreckage of the submersible a week ago, along with pieces of debris from the craft.

Authorities are investigating the cause of the vessel's collapse, which has called into question the regulations surrounding such deep-sea voyages.

A former employee of OceanGate, David Lochridge, had raised concerns over "safety and quality control issues regarding the Titan to OceanGate executive management", but was reportedly "met with hostility" before later being sacked, according to court filings dating back to 2018.

Another industry expert, William Kohnen, had expressed fears that the vehicle's design and construction were not being checked by an independent third party, warning OceanGate that a "single negative event" could undo an "enviable" safety track record that spanned 40 years.

Read more:
What happened to the vessel?
The stories of the 'true explorers' on board

An extensive search and rescue operation - involving vessels on the water, aircraft and remotely operated vehicles (ROVS) underwater - had been carried out after Titan lost communication with the Polar Prince mother ship, an hour and 45 minutes into the two-hour descent to the Titanic on 18 June.

Oxygen had been depleting on board and crews scoured thousands of square miles in a race against time to find the minivan-sized craft.

When the debris field was discovered near the Titanic, the tragedy was confirmed.

On the implosion, rescue expert David Mearns, who knew two of the five victims, said: "The only saving grace is that it would have been immediate - literally in milliseconds - and the men wouldn't have known what was happening."

It was revealed the five on board the doomed submersible spent their last moments listening to pre-loaded music in darkness and had prepared for the journey by eating a restricted diet along with wearing insulated clothing for the colder depths.

Tributes were paid to the victims with Mr Harding described as "a guide, an inspiration, a support and a living legend" by his family, while the Dawoods were "best friends" who "belonged together".

The first British diver to visit the Titanic wreck called Mr Nargeolet an "extraordinary explorer and an incredible individual", while Mr Rush was described as a "risk-taker" with a "vision who wanted to push things forward", by one of his friends.

All five men were "true explorers" a statement from OceanGate had read.

Hamish Harding

Hamish Harding was a 58-year-old British billionaire and chairman of an aircraft brokering company called Action Aviation.

Just before the trip, he announced that he was joining OceanGate as a mission specialist.

Mr Harding holds the Guinness world record for the fastest circumnavigation of the Earth via the North and South Poles by an aircraft - 46 hours, 40 minutes and 22 seconds.

His feats took him to the South Pole and even space.

Shahzada and Suleman Dawood

Both British citizens, Shahzada and Suleman Dawood, were father and son - and members of one of Pakistan's most prominent families.

Their firm - Dawood Hercules Corp - invests across the country in agriculture, petrochemicals and telecommunication infrastructure.

Forty-eight-year-old Shahzada was also on the global advisory board at the Prince's Trust International - founded by King Charles to address youth unemployment.

Suleman, 19, was a university student and was planning a world record attempt to solve a Rubik's Cube 3,700m below the surface of the ocean.

Paul-Henri Nargeolet

Mr Nargeolet, 73, was a former commander who served in the French navy for 25 years.

During his service, he became the captain of the deep submergence group of the navy.

After leaving the navy, he joined the French Institute for Research and Exploitation of the Sea.

Mr Nargeolet had completed more than 35 dives to the Titanic site, and supervised the recovery of over 5,000 artifacts.

Stockton Rush

CEO and founder of OceanGate, Mr Rush, first welcomed tourists to explore the Titanic in 2021.

This was the Titan sub's third voyage, and he was serving as the vessel's pilot.

He became the world's youngest jet transport-rated pilot at the age of 19 and flew commercial jets while in college.

While eyebrows had been raised about the Titan's safety due to a lack of international certification, the 61-year-old entrepreneur argued that regulators were holding his company back and stifling innovation