If there was ever any doubt as to why it is essential to switch off your mobile phone when inside a hospital, a new report has shown that mobile phones do interfere with intensive care equipment.

A team of Dutch researchers found that 78 per cent of hospital ventilators stopped working correctly when a switched-on mobile phone was close by, BBC News reports.

Sixty-one different types of medical equipment - including dialysis machines, external pacemakers, feeding pumps and air humidifiers - were tested in the Critical Care study. The majority were affected by mobile signals, some from distances of up to three metres away.

"The policy to keep mobile phones one metre from the critical care bedside seems warranted," the researchers wrote.

3G handsets less likely to cause disruption

According to the report, 3G handsets are less likely to cause problems than second generation mobile phones.

The Critical Care study also warned that relaxing current bans on using mobile phones in hospitals - as proposed earlier this year by junior health minister Andy Burnham - would be "foolish".