Ambulance workers had to rely on mobile on 7 July

The problem was first raised during the inquiry into the 2005 bombings in London, which revealed senior staff had to rely on mobile phones.

Now a survey by the Association of Professional Ambulance Personnel has found that a lack of hand-held personal radios is a widespread problem.

Apap will debate the issue at its conference this week.

The London Assembly report into the 7 July bombings highlighted the shortcomings of the emergency services' radio communications underground.

It found the absence of a reliable hand-held portable radio system that could function in tunnels, together with the need for runners, heavily compromised ambulance crews' ability to communicate with those overseeing the rescue attempts from the surface that day.

Apap questioned representatives of ambulance trusts across the UK and Guernsey, and had responses from 11 of them.

The association said it was "simply unacceptable" that six of the trusts did not provide personal radios for staff working on their own.

Assurances

Apap wants an assurance that these staff, who include emergency care practitioners and drivers, will no longer have to rely on mobile phones for emergency communication when away from their vehicles.

Mark Weatherhead, Apap's general secretary, said: "With the development of health and safety procedures over the last few years as well as the rise in violent or potentially violent situations in which ambulance staff are placed, it is time for a more robust system to be introduced to reduce the risk to its lowest possible level.

"This should include the introduction of safer, more secure and operationally sound radio systems to ensure each individual's personal safety."

A Department of Health spokesperson said: "Currently different ambulance trusts have different provision for crew safety.