The diphtheria, tetanus and whooping cough (DTP) jab is given to babies by the age of two months.

Although the triple vaccination is commonplace, experts now believe that it might provoke an immune system response which predisposes the body to the lung condition.

However they now believe that delaying the jab by only two months could halve the likelihood of a child developing asthma by the age of seven.

Researchers at Manitoba Institute for Child Health and the University of Manitoba, in Canada, gave 11,531 children four doses of the combined DTP vaccine.

Of the 5,000 babies studied who had the jab at the scheduled age, 13.8 per cent developed asthma.

However only 5.9 per cent of babies who were four months or older at their first immunisation went on to develop the lung condition.

The second, third and fourth doses were given at four months, six months and 18 months.

The study also found a decreased likelihood of asthma if the other doses were delayed, but the strongest evidence was seen in relation to the delay of the first dose.

The Journal of Allergy and Clinical Immunology reported that as many as 12 per cent of children who followed the standard immunisation schedule went on to develop asthma.

The UK has the highest prevalence of asthma in the world in children aged 13 and 14 and one in 11 children is affected.

Dr Richard Halvorsen, author of The Truth About Vaccines, advocates delays between immunisations.

He said: "This is a very interesting study which the Government should look at.

"This study doesn't prove the immunisation schedule we use causes a problem but it is stupid not to consider it."

A spokesman for the Department of Health said: "Several large studies have looked at whether childhood vaccines can cause asthma or allergies - they have found no evidence for this."