The highest-ranking enlisted soldier in the elite unit responsible for protecting the Queen has been cleared of a plot to sell ammunition stolen from the British Army.

Warrant Officer Kirtland Gill, 42, was due to become the first black regimental sergeant major in the Coldstream Guards – recognisable by the distinctive red jackets and black bearskin hats – before he was arrested in an undercover police sting.

He was accused of plotting with Lance Sergeant Rajon Graham, 33, to sell a total of 300 9mm bullets, wrapped in Bacofoil sandwich bags, for £5,800 in cash to an officer posing as a serious criminal involved in the drugs trade.

Graham, who was responsible for the ceremonial kit used by the Coldstream Guards, including swords and bearskins, at Wellington Barracks near Buckingham Palace, admitted four counts of selling ammunition between December 7, 2020 and January 28, 2021 and faces sentencing at a later date.

He was arrested again just two weeks after he entered his guilty pleas for giving someone a revolver loaded with two live rounds at a party in Tottenham, north London, on December 27 last year.

Gill denied conspiracy to sell or transfer ammunition between December 2, 2020 and January 30, 2021 and possession of a prohibited weapon, after a Turkish self-loading pistol was found in his garden shed.

The married father-of-two, who served in Iraq and Afghanistan, was acquitted of both charges by a jury at Southwark Crown Court on Thursday after seven hours and 17 minutes of deliberations.

Graham had been involved in selling ammunition from early 2020 and boasted to the officer, “D”, of his criminal network.

The court heard he took D inside Victoria barracks, the Windsor base of the Coldstream Guards – the oldest continuous regiment in the Army, which carries out ceremonial duties at Buckingham Palace and Windsor Castle.

During the meeting on December 17, 2020, Graham offered to show D live rifles in the armoury, but the officer refused because it was “too risky”.

Gill had been giving an interview to a national newspaper after attaining the rank of warrant officer class 1 – the highest a non-commissioned officer can achieve in the Army.

The court heard how Gill, from Jamaica and the son of a fisherman and a dressmaker, rose through the ranks after joining the Army in 2001 as part of a scheme to recruit soldiers from the Commonwealth.

His commanding officer Lieutenant Colonel David Marsham described him as “firm, fair and professional” and told how he “trusted him”.

Gill, a former tutor at the Sandringham officers’ training academy, was accused of using his role as quartermaster sergeant technical to get access to live bullets, issued for firing practice, to sell on the criminal black market.

But giving evidence, Gill claimed he had “no knowledge” of the plot.

He said his friend Graham, who would visit his family home for barbecues or to play dominoes and help find clients for Gill’s business selling car parts, had left the pistol in his shed.

“He’s leading a double life,” he said of Graham, who is also from Jamaica.

“I would even question if he’s mentally stable.”