British Airways passengers were shocked to find crate after crate of frozen fish arriving on the conveyor belt instead of their luggage at Heathrow airport, according to a BBC report.

Becca Braunholtz, from Sherborne, Dorset, said the boxes of sea bass and sea bream were delivered to Terminal 5 of Heathrow Airport on Monday.

BBC cited her as saying that there were at least 100 boxes of frozen fish on the conveyor belt, all with stickers for JFK Airport in the US.

Passengers said wave after wave of frozen fish kept arriving at the conveyor belt but there was no sign of their baggage.

British Airways staff had no explanation as to why the bungling had taken place with cargo arriving at a passenger terminal. 

Eventually passengers without their luggage were given claim forms and advised to go home.

In a statement, the airline apologised and said most passengers on the flight received their bags as normal.

"We've apologised to our customers and we have been reuniting them with their luggage after realising that something fishy was going on," it added.