The submarine that imploded on its way to view the Titanic had a “critical crack” and “electrical failure”, an expert has revealed.

Mangled parts from the sub, named Titan, were retrieved from the Atlantic Ocean floor with presumed human remains.

Dr Graham-Jones, Associate Professor in Mechanical and Marine Engineering at the University of Plymouth, says sections of the vessel could have started leaking which may have caused an electrical disaster. The five on board on board may have known about the leak, even if it was very minor, before they were killed by an “instant implosion”, he added.

He said: “This could have been an electrical catastrophe. It could have been corrosion, it could have been a fire. Any leakage of water coming through to the electrics could lead to failure as well.

Speaking to the Sun, he added: “Some of the pipes and parts that lead outside could have begun to leak. If you have a wire going outside, then those wires going through land could actually start to leak. They could have corroded.”

Those assessing the wreckage will now be able to find out exactly what went wrong by looking at the patterns of the cracks, he explains.

He added: “The crack could be brittle, or ductile, and related to fatigue and de-lamination. By scanning under an electron microscope, you can see the fatigue and confirm the speed and direction of the cracks.”

The Titan was found at the bottom of the Atlantic Ocean, over 3,658 below the surface of the sea. 

The controller of the submarine, the CEO of OceanGate Expeditions, was killed in the implosion alongside Shahzada Dawood and his son Suleman Dawood who was “terrified” about the expedition but wanted to bond with his father.

British adventurer Hamish Harding and Titanic expert Paul-Henri Nargeolet also died.

The Transportation Safety Board of Canada, which is conducting a safety investigation into the Titan’s mothership, the Polar Prince, said Wednesday that it has sent that vessel’s voyage data recorder to a lab for analysis.