More than 5.7 million smuggled cigarettes have been found by Border Force officers in a lorry that was meant to be carrying children's play equipment.
Staff at the port of Hull 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.
Sam Bullimore, a spokesman for the Border Force, said: "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.
"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.
In the financial year 2010/11, the agency seized more than 650 million cigarettes and 314.7 tonnes of hand-rolling tobacco at the UK border.