The youngest son of Joe Biden, the US vice president, was discharged from the Navy earlier this year for testing positive for cocaine use.

It was evidently not the first run-in with drugs for Hunter Biden, a 44-year-old lawyer and former lobbyist who is now a partner at a prominent Washington investment firm.

He had needed a waiver for an unspecified drug-related incident in his youth when he applied to join the Navy Reserve in his early 40s – a move that surprised his family, including apparently his father.

Mr Biden was commissioned as an ensign in May 2013 and took up a position as a public affairs officer with a reserve unit in Norfolk, Virginia.

The role did not last long. A month later, he was given a routine drug test when he reported for duty and the results came back positive for cocaine. Mr Biden was discharged in February, but the details of the drug test have only now been made public.

In a statement issued through his lawyer, he said: “It was the honour of my life to serve in the US Navy, and I deeply regret and am embarrassed that my actions led to my administrative discharge.”

He did not specifically address the drug use, but said that he respected the Navy’s decision and was “moving forward” with his family’s support.

There was no public response from the vice president’s office.

Mr Biden comes from a prominent political family, which includes not just his father but his brother Beau, who is Delaware’s top legal officer as state attorney-general and is standing as a candidate for governor. Beau Biden is a major in the Delaware National Guard.

Joe Biden had joked about his son’s decision to join the military late in life. “We have a lot of bad judgment in my family,” he said at a rally last year. “My son, who is over 40, just joined the United States Navy. He’s about to be sworn in as an officer, Hunter Biden.”

Telegraph.co.uk