Has José Salvador Alvarenga been reaching for the fava beans and chianti? The 36-year-old sailor survived at sea for more than a year after being cast adrift by a storm. But now the family of his fellow sailor, 22-year-old Ezequiel Córdoba, say the older man turned cannibal to survive. Alvarenga insists Córdoba died because he could not stomach the raw birds and turtle blood that were their only source of food. But Córdoba’s family are suing the Salvadorian fisherman for $1m for eating their relative.

It would not be the first time a survivor in extreme circumstances had tucked in to a fellow traveller. After a plane crash in the Andes in 1972, passengers ate the frozen remains of those who had perished, surviving 72 days before they were rescued. In 2000, three migrants from the Dominican Republic survived for three weeks when their boat engine failed at sea, only by devouring some of the 60 others who succumbed to dehydration and exposure.

But is eating someone’s flesh in such extreme conditions against the law? Not in the UK, according to Samantha Pegg, senior lecturer at Nottingham Trent University. “There is no offence of cannibalism in our jurisdiction,” Dr Pegg says. She points out that Alvarenga’s story is similar to a famous case in legal history. In 1884, a four-man crew sailing from England to Australia were shipwrecked with almost no food. When the 17-year-old cabin boy became ill, two of the men, Stephens and Dudley, decided to kill and eat him. Five days later they were rescued and charged with murder. The third man was not charged, despite eating his companion’s flesh. Although their lawyers argued that killing the cabin boy was a necessity for the survival of the three other men, Stephens and Dudley were convicted of murder and sentenced to death – later commuted to six months’ imprisonment. “This set a precedent that there is no necessity defence for murder,” points out Pegg.

In cases of serial killers or sexually motivated cannibals, the charge is always murder, she says. In Germany, where there is also no offence of cannibalism, a court had to wrestle with a case where a man “offered” himself to be killed and consumed by an IT expert called Armin Meiwes – Meiwes was still convicted of murder. Last year, a German police officer was sentenced to eight-and-a-half years for a similar crime of “murder and disturbing the peace of the dead”. However, because his victim was said to be “willing”, he was not given the maximum sentence.

Other would-be cannibals could face charges of outraging public decency or preventing a lawful burial, says Pegg. In 1988, performance artist Rick Gibson ate human tonsils on the street; he claims to be “the first cannibal in British history to legally eat human meat in public.” With a rise in “body food”, and eating your partner’s placenta, he may not be the last.