USING pesticides on house plants could more than double your risk of developing a brain tumour, a study suggests.

Those who use fly sprays, weedkillers and other chemical treatments on their pot-plants are 2.25 times more likely to develop brain cancer, the findings show.

Around 5,000 Britons are diagnosed with brain tumours each year.

Some can be removed by surgery, but others can cause death quickly.

Little is known about the causes of most brain tumours. The study - one of the biggest of its kind - suggests that chemicals found in pesticides play a role.

The findings come a week after British researchers warned that using pesticides while gardening could increase therisk of Parkinson's disease by more than 40 per cent.

In the latest study, French researchers asked more than 200 male and female patients with brain tumours about their past use of pesticides at work and at home.

They compared the answers with those given by a healthy group of similar age and upbringing. It was found that those who had used pesticides on house plants were more than twice as likely to have developed a brain tumour.

The study, published in the journal Occupational and Environmental Medicine, also found a clear link between pesticide use at work and ill health. Overall, farm workers had almost a 30 per cent increased risk of developing a brain tumour. But those who had used pesticides the most had more than twice the risk.

The researchers, from Victor Segalen University in Bordeaux, concluded: 'These figures suggest that a high level of occupational exposure to pesticides might be associated with an excess risk of brain tumours.

Treatment of house plants was also associated with an increased risk of brain tumour. It is of concern that they are sprayed in closed dwellings and are recommended for use every week.' They added that further research was needed as they could not rule out that differences in diet or exposure to chemicals in household cleaning agents had an effect on tumour development. Nor could they pinpoint which products or chemicals were damaging the brain.

Georgina Downs, of the UK Pesticides Campaign, said: 'This is a clear warning for people to think of other methods to keep plants free of bugs.' The Crop Protection Association, which represents pesticide manufacturers, said there was no conclusive link between pesticides and brain tumours.