British tourists have been cautioned to stay vigilant as a deadly heatwave grips Greece, with temperatures soaring to a terrifying 44C. The unprecedented heat, hitting earlier than usual, has already resulted in multiple deaths and numerous missing persons, intensifying concerns for holidaymakers in the picturesque country.

The latest tragedy involves a missing American tourist, whose body was discovered on a secluded beach on the small Greek island of Mathraki, west of Corfu.

Local media reported that the man had been missing since Thursday and was last seen at a cafe with two female tourists who have since left the island. His body was found on Sunday by another tourist on a remote, rocky beach.

No further details about the victim, including his identity or hometown, have been released.

Mathraki, a heavily wooded island with a population of 100, is just one of several Greek islands where tourists have gone missing or died recently, often due to extreme heat during hikes.

On Saturday, a 74-year-old Dutch tourist was located by a fire department drone, face down in a ravine after being missing for nearly a week.

In another tragic case, British television presenter and author Dr Michael Mosley was found dead on Symi Island, having succumbed to the heat during a hike over rugged terrain. Meanwhile, two French women aged 64 and 73 were reported missing on Sikinos Island after failing to meet as planned.

Authorities continue to search for Albert Calibet, a retired Los Angeles County Deputy Sheriff, who disappeared on Amorgos Island during a solo hike. Calibet, 59, had been reported missing since Tuesday in the sweltering heat.

Amid these incidents, an urgent warning has been issued to travellers. Greek state TV meteorologist Panos Giannopoulos noted the unusual timing of the heatwave: “In the 20th century we never had a heatwave before 19 June. We have had several in the 21st century, but none before 15 June.”

The city of Chania on Crete recorded the highest temperature, reaching 44.5C last Thursday, compounding the crisis with a 3.7 magnitude earthquake the following day.

The record temperatures classify the current conditions as the earliest heatwave in Greek history, typically defined as temperatures exceeding 38C for at least three consecutive days.