President Joe Biden's son Hunter has been found guilty of illegally buying a firearm after hiding his drug use in a landmark US court ruling.

A federal court jury in Wilmington, Delaware, found Hunter guilty on all three firearm charges against him - making him the first ever child of a sitting US President to be convicted of a crime.

Prosecutors said Biden had lied on a form when buying a Colt Cobra revolver in October 2018 when he stated he was not a drug user or addict - despite a problem with crack cocaine.

The conviction comes after the Commander-in-Chief's son had pleaded not guilty to felony charges which included his lies on the government screening document - as well as illegally possessing the firearm for 11 days.

Hunter Biden had stated he was not a drug user or addict - despite a problem with crack cocaineReuters

But Hunter's lawyer, Abbe Lowell, told jurors that his client had not tried to deceive authorities as he had been clean when he bought the gun, and did not consider himself a drug user at the time.

The Delaware trial included prosecution testimony by Hunter Biden's ex-wife, former girlfriend, and sister-in-law, all of whom provided first-hand accounts of his out-of-control addiction in the weeks surrounding his purchase of the gun in October 2018.

Prosecutors also drew attention to text messages, photos and bank records - which they said proved Biden was deep in the throes of addiction when he bought the gun, and knowingly broke the law by denying drug user on the screening form.

The defence called Hunter Biden's daughter Naomi who testified that her father seemed to be doing well when she saw him shortly before and after he bought the gun.

The case had been brought by the Donald Trump-appointed US Department of Justice (DoJ) Special Counsel David Weiss.

Weiss has also charged Hunter Biden with three felony and six misdemeanor tax offences in California, which alleged that he had failed to pay $1.4million (£1.1million) in taxes between 2016 and 2019 while spending millions on drugs, escorts, exotic cars and other high-ticket items.

But Biden has also pleaded not guilty to those charges - for which a trial is scheduled for September 5 in Los Angeles, two months to the day ahead of the crunch US presidential election.