Warren Hill, an intellectually disabled prisoner, has been spared the death chamber just 30 minutes before he was due to die by lethal injection in Georgia despite a US supreme court ban on executions of people with learning difficulties.

Hill, 53, had already taken an oral sedative of Ativan to help calm himself for the gurney before he learned of the stay of execution from the federal appeals court for the 11th circuit. The court agreed to consider the issue of his intellectual disabilities in the light of a 2002 US supreme court ruling that prohibits executions of "mentally retarded" prisoners as a breach of the constitutional safeguard against cruel and unusual punishment.