HAUNTING video footage has revealed the knocking sounds that kept hopes alive in the search for the doomed Titan sub.

A frantic search for the sub’s five passengers captured the world’s attention in June last year.

News of the mysterious banging sounds spread like wildfire across the globe while the rescue mission was underway.

It was previously thought they could be a desperate SOS call from the vessel that was later found in pieces at the bottom of the ocean.

Search teams were alerted after Titan lost contact with its mothership and vanished during an expedition to the Titanic wreck on Sunday June 18, 2023. 

After an agonising wait for news in the second day of searching reports emerged that bizarre noises were detected deep underwater.

The sounds came in 30-minute intervals and can now be heard for the first time in a new documentary.

The chilling bangs came in pairs of two knocks and had a regular hollow beat which is what caught the attention of experts.

Former Navy Submarine Captain Ryan Ramsey tells the Channel 5 documentary: “It could be somebody knocking, the symmetry between those knockings is very unusual.

He added: “It’s rhythmic, it’s like somebody is making that sound, and the fact that it is repeated is really unusual.”

After the sound was first recorded at around 11.30pm on June 20, the US Navy confirmed that it had detected the noises the next morning.

Coast Guard Captain Jamie Frederick admitted he was baffled at the time saying: “With respect to the noises, specifically, we don’t know what they are, to be frank with you.”

The world watched on anxiously as rescuers urgently doubled their efforts to track down the missing sub before oxygen was expected to run out.

Tragically, hopes raised by the mysterious knocking sound were later lost as experts attributed the sounds the noises of other ships in the area.

The Titan was found to have imploded  just metres away from the Titanic killing the five crew in “milliseconds”.

 A US defence official said they heard “an acoustic anomaly consistent with an implosion” just hours after the sub lost contact.

A spokesman for the US Coast Guard said debris found in the search was “consistent with the catastrophic loss of the pressure chamber”.

The mission was orchestrated by OceanGate – a privately owned company that provided crewed submersibles for tourism and research.

OceanGate said “true explorers” Stockton Rush, Brit billionaire Hamish Harding, Paul-Henri Nargeolet, Shahzada Dawood and his 19-year-old son Suleman tragically died on the dive to the Titanic wreck.

Now a new documentary is set to be released to mark a year since the tragedy.

It will go behind the scenes of the multi-million dollar search operation.

Minute by Minute: The Titan Sub Disaster examines the events leading up to Titan’s nightmare expedition to the Titanic wreck.

The documentary, by ITN productions also questions what lessons can be learned from the disaster.

It features the never-before-heard audio of the banging as well as expert opinion on what happened during the search mission that brought the world to a standstill.