The department said it was "extremely unlikely" that anyone would contract the disease after health officials allowed a vaccine to be issued with the wrong expiry date.

A batch of 40,000 doses was sent to doctors with foreign labels bearing the wrong sell-by date. Although they are not harmful, they may be ineffective.

'Extremely uncommon'

A letter has now been sent to GPs advising them to dump the affected supplies and re-vaccinate patients.

A Department of Health spokeswoman said: "Diphtheria is extremely uncommon, and all children have been vaccinated against it in Britain for many years.

"We have sent out a letter asking for the recall of the affected vaccine.

"This is a precautionary measure on the part of the Department of Health and it is very unlikely anyone will contract diphtheria."

The department is instructing doctors to offer second vaccinations if it is found the first jab has not worked.

Highly contagious

But it could be too late for people who have already gone on holiday believing they are protected.

Diphtheria, which kills 2,500 people a year, is a highly contagious disease spread by coughing and sneezing.

If untreated the infection can cause heart failure or paralysis.

The Department of Health says the problem arose because the vaccines had Swiss use-by dates rather than those recommended by Britain.

Diphtheria has more or less been eradicated in Britain.