British sailors have been issued an urgent warning about the threat of being attacked by killer whales following an orca assault on a yacht off the coast of Spain.

Skippers must immediately cut their engines if they encounter killer whales in waters around Britain’s coastline, experts have urgently advised.

Two sailors issued a desperate mayday distress call on Monday after their vessel Azurea came under attack from orcas off Spain’s coast.

The French yacht suffered a battering at approximately 2pm local time, just two nautical miles from Deba. Rescue teams who saved the pair, including a 60-year-old man, described such incidents as “uncommon” at such northern Atlantic locations.

However, a British university expert has refused to dismiss the possibility of similar attacks occurring in future.

Professor Volker Deecke, an academic specialising in marine mammal conservation and behavioural conservation biology at University of Cumbria, warned: “UK sailors transiting the hotspots should definitely familiarise themselves with the guidance. The same guidance applies for sailors encountering any killer whales in Cornish waters.”

The expert told the Daily Telegraph that official guidance for sailors in the Strait of Gibraltar instructs them to immediately halt boat engines and drop sails upon spotting orcas, disable autopilot and echo sounders, and refrain from creating loud sounds to frighten the animals.

Additional recommendations include steering clear of known hotspots entirely and, most importantly, remaining in shallow waters of approximately 20 metres depth. Earlier this month, wildlife experts confirmed the first sighting of Iberian orcas in Cornish waters.

This has raised concerns that British sailors should be particularly cautious in waters around the Southwest of England.

It is believed that incidents like Monday’s close encounter have decreased off the coast of Spain following efforts by authorities to remind sailors of safety protocols.

Dr Javier Almunia, director of the Loro Parque Foundation, told The Telegraph: “The behaviour has reduced, at least in the Gibraltar Strait, by around 90 per cent following the recommendations of the Spanish authorities.”

However, killer whales are known to approach vessels from the stern and hit the rudder before losing interest once they have stopped the boat, a phenomenon that scientists have struggled to fully explain. Some marine biologists believe that the whales may be attacking out of boredom.

Prof Deecke, who studied killer whales for his Master’s degree at a Canadian university, added: “During interactions, the animals remain cool, calm and collected without any of the behavioural signs of aggression such as splashing or vocalisations.”