The waters off Nazaré were made globally famous when Garrett McNamara was photographed surfing a world-record 100 foot wave there in 2011.

No details were given of when it might have been dropped or by which side in any of the wars.

Harbour master Paulo Agostinho said that, “Everything points to it being a bomb containing about 200 kilos of H6” an explosive that is three times more powerful than TNT.

The bomb was dragged up in the nets of the trawler “Mar Salgado”, when it was fishing off the coast of Nazaré, and was taken back to the port for investigation.