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 man, 64, in Chessington for alleged customs offences and he was bailed until August.

The 200kg of European "glass" eels would be worth around £1.2m on the black market.

The haul was shipped back to Spain, where the fish came from.

There is a total EU ban on their export and they are now considered a prized delicacy in the Far East.

Grant Miller, of the Border Force's Heathrow team, said: "This was a significant seizure, the first of its kind for this type of species at export in the UK."

The eels have been a threatened species as numbers have declined by 90 per cent since the 1970s.