Ramsay, 44, travelled to Costa Rica to uncover the illicit trade in shark fins as part of Channel 4’s Big Fish Fight series.
He said: “It is a multibillion dollar industry, completely unregulated. We traced some of the biggest culprits to Costa Rica. The day before we got there, a Taiwanese crew landed a haul of hammerhead sharks – police searched the boat and found bails of cocaine.
“These gangs operate from places that are like forts, with barbed-wire perimeters and gun towers.
“At one, I managed to shake off the people who were keeping us away, ran up some stairs to a rooftop and looked down to see thousands and thousands of fins, drying on rooftops as far as the eye could see.
“When I got back downstairs they tipped a barrel of petrol over me. Then these cars with blacked out windows suddenly appeared from nowhere, trying to block us in. We dived into the car and peeled off.”
Later in the trip he and the film crew managed to talk their way onto one of the fishing boats involved in illegal shark fin trading.
He said: “In a quiet moment I dived from the boat to swim with marlin. I swam under the keel and saw this sack tied to it. I opened it and it was full of shark fins. The minute I threw this bag on deck, everyone started screaming and shouting.
“Back at the wharf, there were people pointing rifles at us to stop us filming. A van pulled up and these seedy characters made us stand against the wall. The police came and advised us to leave the country.
They said ‘if you set one foot in there, they’ll shoot you’.”
