Drivers in the early stages of dementia are as much of a danger as when let loose with a gun, warned an expert calling for a review of current traffic rules and guidance to doctors.

Derbyshire GP Dr Peter Holden who gave the clarion call for a review will address the issue at the British Medical Association's annual conference beginning in Liverpool on Tuesday, 23 June.

While no figures are available for accidents caused by dementia, Holden estimates there could be several thousands annually.

Noting that DVLA (Driver Vehicle Licensing Agency) officials, police and GPs are failing to collect and share information, Holden said: "I expect that this would only affect four or five patients per practice where this is an issue, but we wouldn't accept four or five marauding gunmen.

"There is no one test for dementia, but there are four of five you can make which when you put them together can probably take you in the direction of dementia."

Current traffic rules in the UK require drivers to self-declare whether they are fit to drive at the age of 70 and every three years thereafter.

Medical conditions such as epilepsy have to be notified to the DVLA, but there is no provision for reporting dementia, or suspected dementia.

Doctors ask patients about their driving abilities if they have concerns, but this is too one-dimensional, says Holden, and relies on specific diagnoses or on impairment to the senses.

People with early stages of dementia "slip through the net".

Not all agree on the need for a review, seeing the move as unnecessary scare-mongering and affecting personal mobility.

Andrew White, medical adviser to the Driver Vehicle Licensing Agency (DVLA), believes in aiming at a balance. "All drivers must ensure that they are medically fit to drive and notify DVLA of the onset or worsening of a medical condition affecting this," he said.

Dementia is a brain condition that causes problems with thinking and memory, besides poor judgment ability. Confusion and agitation is also a symptom of the condition.