Scientists say that allergy sufferers are less likely to contract cancer than anyone else.

In the study, children with allergies to airborne substances were 40 per cent less likely to develop leukaemia than others while asthma sufferers were 30 per cent less likely to get ovarian cancer than others.

They believe that adverse reactions stimulate the immune system and thereby help to combat other potentially fatal conditions.

Medical researchers have long suspected an association between allergies and cancer, but studies have led to inconclusive results.

However, in recent years a clear result has emerged pointing to the advantage of having allergies.

Dr Zuber Mulla, an epidemiologist at Texas Tech University, who led the ovarian cancer study, told the newspaper: More work is still needed, but the numbers show that allergy is a statistically significant protective factor.

The report said doctors at Cornell University in New York State found children with airborne allergies also had reduced rates of throat, skin, lung and intestinal cancer.

Canadian studies showed that having an allergy or hay fever lowered the chances of getting pancreatic cancer by up to 58 per cent.

Dr Ronald Crystal, chief of pulmonary and critical-care medicine at Weill Cornell Medical Centre, told the newspaper: Allergies are a general activation of our immune systems. It's hard to prove, and I've heard some scepticism, but it's a concept in this field and the studies add to that.