Thousands of Iranians who have been sentenced to death for drug crimes could be spared following a softening in the country’s law.

Capital punishment has been abolished for some drug offences, and the head of the judiciary has said all cases on death row can be reviewed.

The move is set to be applied retrospectively, meaning some 5,000 prisoners could escape execution.

Iran executes hundreds of people every year, mostly for drug offences.

In August, Iran’s parliament raised the threshold on the amount of drugs that would be considered a capital offence.

Under the previous law, possessing 30g of cocaine would trigger the death penalty but that has been increased to 2kg (4.4lb). The limit on opium and marijuana has been increased tenfold to 50kg.