Hampshire Royal Marine who stole firearms faces years in jail

Martin Shannon, 43, was arrested by armed officers outside a supermarket in Winnall, near Winchester, on September 1 after an undercover operation headed by the National Crime Agency (NCA).

The married defendant, who was said to be suffering from post-traumatic stress disorder, admitted 15 offences at the Old Bailey in October, including selling some of the guns during the covert sting.

Shannon, of Hayley Close, Hythe, near Southampton, had taken a Diemaco (C8) automatic assault rifle and a semi-automatic Sig sauer P226 handgun from RM Poole in Dorset.

He also pocketed thousands of rounds of ammunition, seven high-explosive hand grenades and plastic explosive, which were all recovered following his arrest.

The ammunition included 5.56mm rounds for the assault rifle - high-calibre, high-penetration bullets - and 9mm rounds for Sig-sauer handguns.

They are commonly used by armed forces and law enforcement around the world.

Shannon pleaded guilty to a range of firearms and ammunition offences and was remanded into custody to be sentenced on Friday.

At the earlier hearing, Judge Richard Marks QC said the case was of ‘considerable seriousness’ and a ‘significant sentence is inevitable’.

He told Shannon: ‘It is intended a psychiatric report be obtained to understand something about your background, in particular it is said that you may be suffering from PTSD that may impact on these offences.

‘In the meantime, you will need to remain in custody and I am sure you will understand the fact I am adjourning for a report is not an indication that the case will be dealt with in any other way than immediate imprisonment.

‘The only issue will be as to the length of the sentence.’

Shannon was arrested by officers from the NCA’s Armed Operations Unit, working with the Joint Operations Unit from Thames Valley Police and Hampshire Constabulary.

A Ministry of Defence spokesman said: ‘We take the security of weaponry very seriously and have robust procedures to deter and prevent losses and thefts, which are constantly reviewed.’