Hay fever costs UK business 7.1 billion every year in lost productivity.

A third of hay fever sufferers think the condition has a negative impact on their working lives, nearly 40% say they struggle to concentrate and half say they operate on only 50% capacity when they experience symptoms, according to a report from Kleenex.

But three quarters of managers have not noticed this loss of productivity and fewer than half provide any assistance to hay fever sufferers by providing tissues, pollen filters or fans.

Commenting on the findings, Jean Emberlin, director of the National Pollen and Aerobiology Research Unit, said: "With almost a quarter of our entire workforce being affected by hay fever these figures give us real cause for concern - particularly as businesses struggle to achieve maximum efficiency in the recession."

Most bosses do not allow staff to stay at home if the pollen count is high and a quarter would raise an eyebrow if a staff member called in sick due to hay fever - which explains why most sufferers come to work, no matter how severe the symptoms, according to the report.