A US man is suing a cryonics organisation for the return of his father's head, claiming he can never fulfill his dream of coming back to life because the rest of his body has been cremated.

Kurt Pilgeram, 57, is seeking $1 million (£788,000) from Alcor Life Extension Foundation after receiving the rest of his father Laurence's remains from the facility.

Dr Pilgeram, a prominent scientist who of devoted much his career to researching the aging process, paid $120,000 (£94,600) to preserve his body indefinitely in the hope that one day new technology could bring him back to life.

Alcor, a pioneering non-profit organisation, uses cryonics, an experimental procedure using ultra-cold temperatures, to preserve its patients' bodies.

Mr Pilgeram said that when his father died in 2015, at the age of 90, the Arizona-based organisation sent his ashes to his home in Dutton, Montana.