China nuclear sub sank in its dock, says Pentagon

The BBC showed these images to Mike Plunkett, a naval expert from Janes, who agreed they offered limited insight.

He explained that imagery seen on 29 May “might show a submarine with a X-shaped rudder arrangement”.

However, this alone was not enough to confirm that it was a Type 041, as it could also be a modified Type 039.

He added “it would not be unusual to see a submarine alongside this pontoon” as China has one of its main production facilities for conventional submarines at Wuhan.

A Chinese Foreign Ministry spokesperson said on Friday he was not familiar with the topic and did not provide any information when asked about it at a Beijing news conference.

The incident raises questions about China’s defence industry, which is allegedly riddled with corruption.

China has the biggest navy in the world, with more than 370 ships, and is currently producing a new generation of nuclear-armed submarines, the Zhou-class, of which this was the first.

Taiwan has said it carried out its own investigations into the fate of the submarine and had “a grasp of the situation through multiple intelligence and surveillance methods”, but gave no further details.