Simon Pellett, 37, was arrested in France in a supermarket car park in October 2017 after being caught with a Border Agency van loaded with the illegal goods.
In the van were heavy bags containing 28kg of cocaine, 6kg of heroin, eight automatic pistols, two revolvers, three silencers and ammunition, including a magazine for a sub-machine gun.
Pellett, who had been a UK Border Agency official for 12 years, was sentenced on Friday at Isleworth Crown Court after being convicted earlier this week of several charges.
“This was a shocking breach of trust and duty for a man whose job was to protect our border from just this kind of criminal activity,” Judge Robin Johnson said.
Pellett, of Dover, and two accomplices, Alex Howard and David Baker, were arrested in Loon-Plage, near Calais, by French and British authorities who swooped following a joint operation.
The combined street value of the “high purity” drugs was some £3.4 million.
“This was a major enterprise and the drugs had they pervaded the market would have caused untold misery,” Judge Johnson said.
“The guns were desirable on account of their size, their firepower and the fact some were new.
“These weapons were the tools of the trade for those connected with the drug trade to protect their territories. I have no doubt they could have been used to maim or murder.”
The judge said Pellet, when caught, claimed he thought he was only transporting a “mysterious oil”.
He was convicted on three counts of conspiracy to be knowingly concerned in concealing goods with intent to avoid prohibition on importation, namely cocaine, heroin and firearms.
He was also sentenced for one count of misconduct in public office because he was a Border Agency officer.
Baker, of Beckenham in south London, and Howard, of Sittingbourne in Kent, also received heavy sentences on Friday.
On the day of the arrest, Baker, 55, drove his own car from a hotel in Belgium to the car park in Loon-Plage and loaded the bags into Pellett’s Government van as authorities watched on.
Howard, a roofer by trade, had been keeping lookout nearby when he was caught, later claiming he thought he was helping smuggle cigarettes.
Baker was jailed for 20 years and 115 days on three charges relating to the cocaine, heroin and firearms.
Howard received 10 years and 115 days in prison over two charges relating to the drugs only.
Defence laywers argued the trio were simply couriers of the goods and others higher up had organised the smuggling.
“Those at the bottom of the chain get their hands dirty,” Pellett’s lawyer Nigel Lambert QC said.
Pellett had no prior convictions and was “gripped” by a gambling addiction and depression at the time of the plot, the court heard.
“It was an amalgamation of these things that led him to act so obviously out of character,” his lawyer Nigel Lambert QC said in mitigation.
Mark Leech, Editor of The Prisons Handbook for England Wales remarked:
“The question for me is not why he did it, we know why he did it – money – it’s how many times he successfully got away with it in the past before he was caught – you have to be either very unlucky, or downright stupid, to get caught in something as big as this the first time you give it a go.”