The UK’s plan to leave the Customs Union has fuelled fears of an upsurge in smuggling on the Irish border.
Different tax regimes on either side of it for the first time could increase the opportunity for illegal profit-making.
It is a serious concern for Fianna Fail’s Brendan Smith, a member of the Irish parliament from a border constituency.
He said: “Criminal gangs have become big smugglers. What I fear is border checkpoints and different pricing and different trading conditions both sides of the border.
“That will give, unfortunately, an impetus to those criminal gangs in their smuggling behaviour.”
Ireland has a long history of smuggling. Illicit journeys from one jurisdiction to the other were a by-product of partition.
Elderly people vividly recall their attempts to evade the customs when transporting groceries for a meagre profit.
Peadar Morgan, who learned to smuggle while still at school, explained: “We got two ropes and we tied 30 dozen of eggs, a wooden case, on our backs to take from the south up to the north.
“We were just going up the field, about 100 yards, when the next thing we heard this shout: ‘Customs’.
“One of them caught me by the arm… and when I looked around, well let’s just say the customs man and myself fell out.”
Sam was one of the more notorious. His smuggled tea, butter and cigarettes and his exploits landed him in prison twice.
The newspapers called him “Ulster’s Robin Hood”. Neighbours even persuaded him to stand for election.
But the cultural ambivalence about smuggling was shattered by the outbreak of the Northern Ireland troubles.
The exploitation of the border became a commercial operation with the IRA laundering fuel to fund its terrorist campaign.
Crime author and journalist Paul Williams explained: “This multimillion pound smuggling operation continued over 30 years on an industrial scale
“It was right under the noses of the British Army watchtowers and helicopters and on the other side, intensive Garda activity and Irish Army activity and Customs activity.
“Now that was perhaps the hardest border you could get.”
There are at least 12 different criminal gangs operating on the border now, trafficking fuel, drugs and alcohol among other things.
Before the Brexit vote, their activity was already costing the Irish Exchequer an estimated €800m (£703m) per year.