Parents are being urged to ensure their infant's inoculations are up to date after a child died of a suspected case of diphtheria.

The child, who has not been identified, died after initially being treated at Sutton's St Helier Hospital before being transferred to St Thomas's Hospital.

The Health Protection Agency (HPA) says it is rare for people to die from diphtheria - an illness which affects the upper respiratory tract, nose, throat, voice box and upper windpipe and occasionally, the skin.

Symptoms can include a sore throat, fever and swollen lymph glands in the neck. More severe symptoms can occur if the diphtheria is caused by a strain that produces toxins. These include heart failure and paralysis.

The disease is rare in the UK because of the success of the country's vaccination programme.

A few isolated cases of the disease are seen but are usually in unvaccinated people who have picked up the infection abroad.

Professor Peter Borriello, from the HPA, said: "It is rare for people to die from diphtheria as severe infection is prevented by immunisation and the majority of children are routinely immunised against diphtheria in the UK. This child had not been immunised.

"We have taken action to prevent the infection spreading to others. The bacterium that causes diphtheria can be carried without it causing any symptoms and therefore as a precautionary measure, samples have been taken from those who came into close contact with the child. All these contacts have been prescribed antibiotics and booster immunisations where necessary.

He added: "We recommend that if people are not up to date with their routine immunisations they should contact their GP to arrange them."