Mobile phones should come no closer than one metre to hospital beds and equipment, new research has warned today.

A study to be published in the online open access journal Critical Care details incidents of electromagnetic interference from 2G and 3G mobile phones which occurred at a distance of three metres.

The Dutch research team examined the effects of GPRS and UMTS signals on critical care equipment such as ventilators and pacemakers. Almost 50 incidents were recorded, 75 per cent of which were described as 'significant' or 'hazardous'.

Hazardous incidents varied from a total switch off and restart of mechanical ventilators, to complete stops without alarms in syringe pumps and incorrect pulsing by an external pacemaker.

The 2G GPRS signals caused the highest number of electromagnetic interference incidents at over 60 per cent whereas the 3G UMTS signal was responsible for just 13 per cent.

Electromagnetic interference incidents also occurred at a greater distance with GPRS with a hazardous incident even at three metres.

Dr Erik van Lieshout, lead researcher at the Academic Medical Center at the University of Amsterdam, said: "Our work has real implications for present hospital restrictions on mobile phone use in patient areas.

"It is unlikely that mobile phone induced electromagnetic interference in hospitals will be eradicated in the near future, so the one metre rule currently in place should continue as it is relatively safe."