AMONG the five people on board the missing submarine near the wreck site of the Titanic is a former pupil of The King's School in Gloucester, British billionaire adventurer Hamish Harding.

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.

Rescue teams are now racing against the breathable air clock after noises were detected from the search area for the missing deep-sea vessel near the wreck site of the Titanic.

The others on board are Shahzada Dawood, his son Suleman and OceanGate’s chief executive and founder Stockton Rush, reportedly together with French submersible pilot Paul-Henry Nargeolet.

On Tuesday the US Coast Guard estimated the 6.7 metres (22ft) long OceanGate Expeditions vessel had just 40 hours of oxygen left.

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 US Navy experts for further analysis which will be considered in future search plans.”

The Explorers’ Club, of which Mr Harding is a founding member, shared an upbeat message on Wednesday morning.

President Richard Garriot de Cayeux said in a statement: “There is cause for hope, that based on data from the field, we understand that likely signs of life have been detected at the site.

“They precisely understand the experienced personnel and tech we can help deploy… We believe they are doing everything possible with all the resources they have.”

Mr Garriot de Cayeux said they are ready to provide the UK-based Magellan’s remotely operated vehicle (ROV) that is certified to travel as deep as 6,000m.

In a statement on their website, deep water specialists Magellan said they were contacted by OceanGate on Monday and “immediately” offered knowledge of the site and expertise in operating at depth.

The company added that it has been working with UK and US agencies to move its specialist equipment and support crew to St John’s, Newfoundland, following instructions to mobilise from OceanGate.

Chris Brown, an explorer and friend of Mr Harding, told BBC Breakfast that making “banging sounds” is “just the sort of thing I would have expected Hamish to come up with”.

Retired UK navy rear admiral Chris Parry said that without an “emitting signal” from the deep-sea vessel near the wreck site of the Titanic it will be “impossible” to find it in the timescale.