A HAMPSHIRE Royal Marine reservist is facing years in jail after being caught in Winchester in an undercover sting trying to sell guns and ammunition.

Over four years, Martin Shannon, 43, of Hythe, Southampton, took guns, ammunition, explosives and grenades from his base in Poole and buried them in hides in the New Forest.

He was snared by a National Crime Agency undercover officer who handed him £10,000 for the sale or loan of ammunition and guns at a meeting in a pub car park near Newbury.

Following his arrest at Tesco in Winnall, Shannon told officers that he had thought to make money selling the guns to “Great Train Robber-types” who would open safes in a “cloak and dagger” style before “running off into the sunset”.

The cash-strapped defendant was suffering from post-traumatic stress disorder at the time and pleaded guilty to 15 offences at the Old Bailey.

Ahead of his sentencing, Judge Richard Marks QC told him that whatever his motives were, once he had handed over the guns, they were out of his control.

The Ministry of Defence had launched its own inquiry after supplies went missing from the Poole base where Shannon was stationed over a period of four years.

Shannon had joined as a Royal Marines reservist in 1996 and was also a commercial diver and HGV driver.

He was questioned by MoD investigators after an assault rifle and self loading pistol went missing from the base in October 2012 but he denied involvement.

On the evening of September 1, Shannon had met the NCA undercover officer in Chieveley near Newbury.

The defendant had brought with him ammunition, grenades and pyrotechnic munitions which he sold for £5,000.

He also agreed to lend him a Diemaco assault rifle and Sig-sauer P226 handgun for an extra £5,000, handing them over with a sawn-off shotgun.

Shannon told the officer the stash was “military grade” and the grenades were “big stuff”.

One of the guns was loaded when the defendant showed it to the officer, the court heard.

Shannon told the officer the deal was about “him wanting to make some money”.

He described himself as “old school”, “old-fashioned” and “loyal”, and was “happy to be part of a team”.

He also showed the officer how to load and unload a weapon, the court heard.

After the meeting, he was tracked to the Tesco supermarket in Winnall, near Winchester, where officers moved to arrest him safely.

A search of his home uncovered 500 rounds of ammunition and a stick of plastic explosive.

Some of the bullets were hidden inside a Kenco coffee jar.

Following his arrest, Shannon was asked if he had any issues and he said it would “all come out in the wash”, the court heard.

In an interview, Shannon explained how he had picked up and kept the guns which were meant for use in the training range.

The self-confessed hoarder said he had stored them in watertight containers he buried in the New Forest.

Shannon admitted there was another weapon buried in a hide and took officers to the spot.

Specialist officers later discovered a bolt-action shotgun buried near the railway line.

In interview Shannon said he thought the buyers would be stealing from drug dealers or “Great Train Robber types” who were after money and did not hurt people.

The court heard he had imagined “cloak and dagger” operations involving cracking safes and “running into the sunset”.

He admitted all the charges including transferring a prohibited weapon, having explosives, possession of ammunition, transferring prohibited ammunition and possession of a firearm without a certificate.

Sentencing was adjourned until 2pm tomorrow.