Prince William in trouble after losing gun

The 24-year-old royal mislaid the powerful machine gun on Friday morning. It is one of the most embarrassing errors a soldier can be guilty of.

The incident will have serious consequences for the prince who, until now, has proved a model cadet and is just weeks away from passing-out of the Royal Military Academy near Camberley, Surrey.

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He is said to be in line for the prestigious 'Sword of Honour', awarded to the most outstanding student of each intake. But losing his gun is a serious black mark on his record.

William was so concerned that he borrowed a fellow cadet's bicycle and spent almost two hours pedalling around the countryside campus looking for it.

But he was forced to return to the ranges empty-handed to face, what has been described as "an absolute rollicking".

Although it was not loaded with live ammunition at the time, the L86 Light Support Weapon is a fearsome weapon capable of rattling out 775 rounds every minute. It is a more powerful version of the British Army's standard issue SA80 rifle.

"William was due to spend a day on the ranges in preparation for a major exercise in Wales this week," said the source.

"He was given his SA80 rifle, the weapon that is personally assigned to him throughout his time at Sandhurst, but also signed out an LSW as he needed to ensure he was fully familiarised with it.

"All of the cadets, including the prince, were given a full briefing first thing in the morning but it seems that he mislaid it sometime after that.

"William was really panicking as he knew he was in serious trouble.

"He even borrowed on of his mate's bike and spent several hours frantically scouring the academy for it.

"Much to his embarrassment, it was handed in about two hours later by another cadet. I'm not sure where it was found, but William was still in a lot of trouble."

The source added: "Fortunately there wasn't any live ammunition in the gun as cadets aren't given any bullets until they are ready to fire on the range. But that wouldn't have helped him much.

"Losing your weapon is one of the worst mistakes you can make. It's a real shame, though, if it costs him the Sword of Honour as William is shaping up to be a superb army officer."

William, who is second-in-line-to-the-throne, plans to follow his younger brother into The Household Cavalry's Blues and Royals regiment if he successfully passes out in December.

Like Harry, he also hopes to become an armoured reconnaissance troop leader, commanding around a dozen soldiers and four Scimitar tanks, which are used to scout out the enemy in the heat of battle - although it is unlikely that the future king will ever see frontline service.

It is understood that Harry has asked top brass at his barracks in Windsor for the day off so that he can watch his brother's passing out.

His grand-mother, the Queen, has already agreed to take the ceremony while other senior royals including his grand-father, the Duke of Edinburgh, Prince Charles and the Duchess of Cornwall are also due to attend.

A Sandhurst spokesman tonight confirmed that there had been an incident on the ranges involving William's gun.

"In fact Officer Cadet Wales's weapon was picked up and used by another cadet who handed it back a couple of hours later, so it wasn't really missing at all," he said.

On arriving at Sandhurst cadets are each issued with their personal weapon, an SA80 rifle, but will be taught to use a number of other guns, including the L86 Light Support Weapon.

These are kept in the college's secure armoury and, for security and safety reasons, only signed out to cadets as and when required.

Following a safety briefing on Friday, William was given his gun which he should have taken straight up to the firing range and handed straight back once the exercise was over.