Video report by ITV News Correspondent Richard Pallot.
The ringleader of a gang that smuggled more than £100,000 worth of guns into the UK, that could have unleashed "carnage on a terrifying scale", has been told he could face a life sentence.
Harry Shilling, is said to have bragged "we now officially gangsters" after the haul of lethal weapons arrived in the UK from France.
The 23-year-old, along with Michael Defraine, 30, was found guilty of gun smuggling and possessing firearms with intent to endanger life following a trial at the Old Bailey.
Three other members of the gang, skipper David Payne, 43, Richard Rye, 24, and Christopher Owen, 30, had already pleaded guilty.
Two other defendants John Smale, 58, Jennifer Arthy, 42, were cleared of the charges they faced.
The 'Keyser Soze' ringleader
Harry Shilling is said to have been the mastermind behind the plot. The prosecution compared him to Keyser Soze from the Usual Suspects, pretending to act the fool while pulling the strings of crew behind the scenes.
Michael Defraine, 30, acted as Shilling’s “man on the continent,” arranging transportation of the guns.
Richard Rye, 24, was a “loyal lieutenant” to Shilling and acted as a go-between with others who played a part in bringing the firearms.
David Payne, 43, was skipper of the Albernina, which was used to transport the guns
Christopher Owen, 30, also helped to buy and customise the boat
Police uncovered 22 VZ-58 assault rifles and 9 Skorpion sub-machine guns.
The assault rifles, which were Czech and closely resemble AK47s, were designed for use by the military but had been deactivated. They had then been reactivated for resale.
The Skorpion sub-machine guns had also been converted so they could fire again.
Video: Martin Parker, from the UK National Ballistics Intelligence Service demonstrates the power of the smuggled weapons.
Where did the guns come from?
They had been sold legally by a firm called AFG in Slovakia, in Eastern Europe, as deactivated "acoustic expansion weapons" firing blanks, according to investigators.
How did they get into the UK?
On August 10, the guns were brought into the country from Boulogne in France, up the River Medway to north Kent aboard a specially adapted boat, the MV Albernina, which was skippered by David Payne.
"We are officially gangsters"
On arriving back in the UK, Shilling sent a message to Michael Defraine, "We now officially gangsters," and Defraine replied "F***ing nice one".
In another message, Shilling wrote: "Duck and run for cover b*****s. We are a firm ant we', and Defraine responded:"Proper heavy and armed to the teeth no one wants beef fam."
What were the guns going to be used for?
It is thought the gang planned to find buyers on the UK drugs market and criminal gangs who lend or hire out the deadly weapons.
Shilling is also known to have exchanged messages with a mystery contact "B" to arrange the onward supply of the guns.
Rob Lewin, head of the NCA's Specialist Operations Unit,said: "Either Shilling was going to use these for his own purposes, for his own criminal enterprise or he was going to sell them on with ammunition for profit."
How was the gang caught?
The authorities became aware of plans to buy guns around the time the gang bought the Albernina.
Kent Police had already been investigating Shilling and called in the National Crime Agency.
On August 11, Shilling, Defraine and Rye went to shops to buy tools,bags and other items they needed to bury the weapons. Two gang members were arrested in Homebase car park, one was tackled in a McDonald’s, while the others were intercepted
Smale and Owen had donned blue gloves to unload the cargo from the MVAlbernina, before armed NCA officers swooped in and surrounded them.
How does the haul match up to other similar seizures?
The National Crime Agency (NCA) said it was probably the biggest seizure they had seen on the mainland of these types of weapons.
Rob Lewin, head of the NCA Specialist Operations Unit, told ITV News “these are mass casualty weapons".
All five men will be sentenced at a later date and Judge Michael Topolski QC said he will give "serious consideration" for a life sentence for Shilling.