Border Force officers in Hull have found more than 5.7 million smuggled cigarettes in a lorry which was meant to be carrying children's play equipment.
Staff at the port found the haul on an unaccompanied trailer that arrived on a ferry from Rotterdam.
The load was listed as "kindergarten equipment" but actually contained 5,760,000 cigarettes, worth more than £1,410,000 in unpaid duty.
It comes less than three weeks after 10.5 million cigarettes were seized at nearby Immingham.
"We will continue to make life as tough as possible for those people who seek to smuggle cigarettes into the UK.
"This is not a victimless crime, as it defrauds the public purse out of huge sums of money and undercuts those traders who ply an honest trade.
"Anyone who chooses to buy counterfeit cigarettes may also be contributing to the funding of serious organised crime groups.
– Sam Bullimore, UK Border Force
"We have expert and experienced staff who, supported by sniffer dogs and the latest technology, work round the clock to keep our border secure."
The seizure was made on Thursday afternoon and the shipment will be destroyed."