The commission’s statement made no mention of the Liaoning project, giving only brief details of the case and saying that the investigation had concluded and that the party leadership had approved Sun’s expulsion. The case is now being handled by the country’s judicial bodies.

“As a senior cadre and responsible leader of a state-owned enterprise, Sun Bo has abused his authority and was disloyal to the Communist Party,” the statement said.

“He committed serious violations of party discipline and did nothing to correct his mistakes even after the 18th party congress,” the graft-buster said, referring to the 2012 meeting at which a nationwide anti-corruption drive was announced.

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That campaign, driven by President Xi Jinping, has snared more than 1.3 million party officials at various levels of government, from powerful “tigers” to low-ranking “flies”.

State-owned CSIC plays a key role in developing and building naval vessels including nuclear and conventional submarines and aircraft carriers. It is currently working on the first Chinese-built aircraft carrier, the Type 001A, at its shipyard in the northeastern port city of Dalian, Liaoning province. The vessel’s design is based on the Liaoning, China’s only fully operational aircraft carrier.

One of the sources close to the military said it was unlikely the authorities would make public details of Sun’s crimes since they would involve “state secrets”.

“His case is complicated and involves a lot of state secrets that can’t be disclosed, so the authorities would only say he was being held on ‘corruption charges’,” the source said.

China bought the Liaoning – an unfinished Kuznetsov-class aircraft carrier originally designed for the former Soviet navy – from Ukraine in 1998, and CSIC spent a decade refitting the vessel before it was commissioned in 2012.

The investigation into the CSIC general manager has had a huge impact on the shipbuilder, according to a third source who is close to the company.

“The whole Type 001A has been designed and built based on the original design and refitting experience of the Liaoning,” the source said. “All the staff at CSIC have been told not to say anything about Sun, so you can imagine how sensitive his case is.”

The Type 001A is still undergoing sea trials, and military experts expect it to be handed over to the Chinese navy before October next year – in time for celebrations marking the 70th anniversary of the founding of the People’s Republic of China.

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In its statement, the graft-buster also said Sun had been disloyal to the party, had taken part in “feudalistic superstitious activities” and had refused to cooperate with the investigation.

Sun, who attended a launch ceremony for the new aircraft carrier in April last year, was last seen in public on June 11, when he visited one of the shipbuilder’s subsidiaries, according to a report in Beijing Youth Daily.

Sun built his maritime career in Dalian, rising to the party leadership at CSIC in 2009 and also serving as chairman of Dalian Shipyard Group. He was appointed general manager of the shipbuilder in 2015, under Hu Wenming as chairman.

It is not the first time the shipbuilder has run into trouble. In 2016, Liu Changhong, then head of discipline inspection at CSIC, was investigated by the top anti-corruption watchdog. He was subsequently expelled from the party and in September last year it was announced he would face prosecution on suspicion of taking bribes.