A passenger allegedly tried to smuggled 600,000 endangered live eels onto a plane from Heathrow.
The slipper customers, bound for Hong Kong, were spotted hidden under a load of chilled fish at Heathrow Airport.
Border Force officials arrested a 64 year old man for customs offences.
The 200kg of European “glass” eels would be worth around $2.1m on the black market.
Glass Eels are a prized delicacy in the Asia.
The eels have been a threatened species as numbers have declined by 90 per cent since the 1970s.