Doctors now have the power to report patients they consider to be unfit to drive to the authorities, without their permission.
New guidelines that came into effect today outline how GPs have a responsibility to alert the Driver and Vehicle Licensing Agency (DVLA) when a patient is driving against medical advice.
However, the General Medical Council emphasises that doctors should "make every reasonable effort" to dissuade a patient from driving if they believe they are unfit to do so, and only report them to authorities if they think there is a "risk of death of serious harm" to others.
It also stresses that GPs should make an effort to make a patient aware of their intentions to disclose personal information prior to contacting the DVLA.
The new guidelines have been brought in to help doctors balance their legal and ethical duties of confidentiality with their protection responsibilities to the wider general public.
Steve Gooding, from the RAC Foundation motoring research charity, told the Daily Mail some drivers may fear losing their licence if they declare certain illnesses to the DVLA.
"I would appeal to all drivers to ensure that they declare any relevant medical conditions to the DVLA to help keep all road users safe."
The new guidelines come after a number of serious accidents that involved pensioners who weren't considered fit to drive, as well as increasing calls for elderly motorists to retake their driving tests.
A young mother was killed in 2014 when a pensioner hit her with his car after pressing the accelerator rather than the brake. He was jailed for causing death by dangerous driving.
In 2012, a partially-sighted 87-year-old was also sent to prison after he fatally injured another pensioner in an accident. He had lied about his eyesight in a bid to retain his licence.