Doctors are warning parents to be extremely careful not to leave tiny flat button batteries lying around because of the risk that children could swallow them.

Over the past few years at least 16 children have been seriously injured – two of whom died – after swallowing the batteries which are used in watches, hearing aids and on key chains.

‘The acid inside the battery eats through a child’s gullet in no time,’ paediatrician Lissy de Ridder from the Erasmus university medical centre told the AD. The damage can lead to permanent problems with eating and breathing, the paper said.

Parents who suspect their children may have swallowed a battery are urged to take them to a hospital accident and emergency department immediately. ‘The first sign is a child who is reluctant to eat,’ De Ridder said. ‘If a child begins to spit blood, the damage will already be considerable.’