This is a terrifying haul of lethal handguns destined for London crime gangs which were seized by officials at the Channel Tunnel terminal in France.

They were discovered in concealed compartments in a trailer attached to a Mercedes van as it prepared to enter the tunnel at the Coquelles terminal.

Border Force officials swooped after a joint investigation by the National Crime Agency and detectives from Scotland Yard’s organised crime unit.

Searches revealed a cache of 79 “viable” 4mm and 6mm handguns and a large quantity of ammunition, all hidden in specially adapted concealments in engine blocks.

Detectives believe the weapons had been smuggled from eastern Europe to be sold to organised crime gangs in London.

Seven people were arrested when the van was stopped in France but six, all Polish nationals, including four women aged 15, 17, 58 and 41, were later released without charge.

Police described the seizure as “very significant” and one of the largest of its kind.

Detective Chief Superintendent Michael Gallagher, of the Met’s Organised Crime Command said: “This joint operation highlights how we can work effectively with other agencies to combat serious and organised crime. I have no doubt that a number of these weapons were destined for the streets of London, where they would have caused misery and unspeakable damage to the community.”

The operation comes as figures show a 28 per cent rise in the number of shootings in London in the 12 months to April, compared with the previous year.

Officials from the National Crime Agency say guns are being smuggled into the UK from eastern Europe where they are cheap and easily available.

While police stress that gun crime is relatively low in the UK, they say they are seizing more guns on the streets. There are growing fears that guns obtained by crime gangs could fall into the hands of terrorists.

Graham Gardner, NCA Deputy Director of investigations, said: “This joint operation has resulted in a large number of viable firearms being taken out of circulation before they could reach the UK.

“Whilst we are in the early stages of our investigation, I believe these weapons were intended for criminal use in either London or across the UK and it goes without saying the risk they would have posed to the public.”

He said handguns were the favoured weapon of criminal gangs because they were easily concealed but still lethal.

Her added: “These weapons are unusual because they are low calibre compared to other handguns but they are no less lethal. The bullets are small but they can still kill.”

NCA officials say they are also seeing an increase in the number of weapons being ordered over the dark web and delivered to addresses in the UK via the parcel system.

Two men Janusz Michek, 59, a Polish national, who was arrested at the scene, and Denis Kolencukov, 23, originally from the Czech Republic but living in Slough, were charged with conspiracy to possess firearms.

They were due to appear at Uxbridge Magistrates Court this morning.