Cruise lines have insisted their submersibles are safe following the deaths of five people on board the OceanGate Titan sub (pictured) which is believed to have imploded while descending 3,800 metres to view the Titanic shipwreck.

Several expedition cruise lines feature submersibles, which allow passengers to take underwater excursions.

A spokesperson for Scenic Cruises insisted excursions offered on its submersible, called Scenic Neptune, are safe, saying the vessel is “highly regulated” and offers a “safe experience”.

“All at Scenic Cruises are saddened by the outcome and the news of lives lost onboard the Titan Submarine,” the company said.

“Our own submersible, Scenic Neptune, offers a completely different experience and is built to dive to depths of 200-300m though does not dive beyond 100m which provides the best viewing experiences.

“Scenic Neptune has been built to conform with classification society rules. It is a highly regulated and safe experience.

“Our thoughts are with those who have lost loved ones on board Titan and the wider crew impacted.”

Viking shared a statement on its website assuring customers its four submersibles feature “a multitude of safety systems and built-in redundancies in case of failures, and take guests on dives of less than one hour, and never deeper than 300m.”

The company added: “The training our submersible pilots and surface officers receive exceeds all recommended industry standards, and regular safety drills anticipating every possible emergency situation ensure that each dive is conducted under the most stringent of safety conditions.

“Each one of our four submarines has been certified by DNV, the world’s leading maritime classification body and each of our two expedition ships carries equipment on board for the very unlikely event that recovery of a submersible from under water should be necessary.”