GPs must tell the DVLA if a patient continues to drive when they are not medically fit, according to new guidelines for doctors.

In draft guidance, the General Medical Council said doctors have a public protection duty to inform authorities if a patient is driving against medical advice.

Doctors do not need a patient's consent to inform the DVLA when a patient has continued driving.

The strengthened advice is part of a public consultation on the GMC's core guidance on confidentiality.

The guidance says doctors must disclose information if there is a need to protect individuals or the wider public from the risks of death or serious harm. This can include risks of violent crime, serious communicable diseases, or risks posed by patients who are not fit to drive.

Niall Dickson, chief executive of the GMC, said: "This is difficult territory - most patients will do the sensible thing but the truth is that a few will not and may not have the insight to realise that they are a risk to others behind the wheel of a car.

"A confidential medical service is a public good and trust is an essential part of the doctor-patient relationship.

"But confidentiality is not absolute and doctors can play an important part in keeping the wider public safe if a patient is not safe to drive.

'We are clear that doctors carrying out their duty will not face any sanction - and this new guidance makes clear that we will support those who are faced with these difficult decisions."

It comes as a number of high-profile cases involving drivers with medical conditions have been examined in fatal accident inquiries.

Last week a sheriff said that a bus driver who knocked down and killed his colleague should have followed medical advice after previous faints to avoid losing consciousness while driving. David Logue had blacked out twice at the wheel previously but had had his driving licence reinstated. The third blackout that led to Jim Lochrie's death on March 21, 2012, was blamed on dehydration, despite Mr Logue's doctor having given him advice in 2008 to avoid becoming dehydrated.

Meanwhile, the FAI into the fatal Glasgow bin lorry crash heard claims that driver Harry Clarke broke the "bond of trust" between a patient and doctor when he failed to give full details about a previous blackout.

He lost consciousness while working as a driver for First Bus in April 2010 but he told his GP that he passed out in a hot canteen, leading to the episode being categorised it as a "simple faint" which did not require any further action by the DVLA.

Six people died when Mr Clarke lost consciousness behind the wheel of a bin lorry in Glasgow city centre on December 22, 2014. He has since resigned from his position with the council.

Neil Greig, director of policy and research at the Institute of Advanced Motorists, said: "Clarifying the role of GPs is a very positive road safety move.

"Our research shows that drivers are much more likely to listen to a medical professional giving them advice about giving up driving than to their friends or family."

Steve Gooding, director of the RAC Foundation, said: "The worst thing motorists can do is ignore medical advice. If they don't tell the DVLA about something that impacts on their ability to drive safely, then their GP will."