By Nick Triggle
BBC News health reporter
Patients' lives are being put at risk because thousands of doctors working in the UK may not have sufficient English language skills, doctors warn.
A third of the UK's 230,000 doctors are from overseas
All medics from outside Europe are tested by the General Medical Council before being allowed to work, but those from within Europe are exempted.
Medical organisations say it is essential that all doctors can communicate effectively with patients.
The government said NHS trusts should ensure staff had adequate English.
There are more than 230,000 doctors registered with the GMC, of which 162,000 are UK nationals, 12,000 from the European Economic Area - the EU countries plus Norway, Iceland, Switzerland and Liechtenstein - and 60,000 from the rest of the world.
Dr Surendra Kumar is president of the British International Doctors Association and a former member of the GMC's registration committee, which determines the requirements doctors need to fulfil to show they are fit to practise.
She said: "Quite often doctors from outside Europe have better language skills than those from within Europe because they may have trained in English.
"But the problem is that we cannot test those from Europe.
"It was immensely frustrating when I was on the registration committee.
"Patients lives are being put at risk because some doctors just do not have good enough communication skills, and since they are not tested it only becomes apparent when they are dealing with patients."
Dr Edwin Borman, chairman of the BMA's international committee added: "It's essential that all doctors, whether from Europe or outside Europe, can communicate effectively, both with patients and colleagues.
"We know that hasn't always happened under the present system."
He added: "Currently, NHS trusts have responsibility for ensuring the doctors they employ are proficient in English, but the BMA believes the GMC should also have the power to test doctors' language skills."
A spokeswoman for the GMC agreed it was an issue and that it would like to take on the responsibility.
However, she added: "We want to be able to assure patients that all doctors on the medical register are able to communicate effectively in English."
The Department of Health pointed out that it was up to NHS trusts not to employ doctors with insufficient English skills.
She added the department's code of practice recommended that foreign doctors demonstrate a level of English language proficiency "consistent with safe and skilled communication with patients, clients, carers and colleagues".