The General Medical Council (GMC) has warned that patients may be being put at risk because of a loophole in the system for checking the backgrounds of doctors from overseas.

A medical accident which led to the death of David Gray, 70, last year highlighted the issue of doctors who trained in other countries but now work in the NHS.

Mr Gray died after a German doctor, Daniel Ubani, administered a huge overdose of diamorphine – a drug he was not familiar with using.

European law means qualified doctors from other EU countries do not have their clinical competence tested before they work in the UK, even though training standards are not uniform across the EU.

However, a shortage of doctors means many NHS trusts have little option but to use medical professionals from other countries as locum cover.

Regulations governing freedom of movement of workers also mean that authorities in other EU countries do not have to supply the GMC with details of a doctor’s work history, meaning a medical professional who has been struck off may be able to obtain a job in the UK.

The GMC’s deputy chief executive Paul Philip told the Telegraph: "We can try to get as much information as we can – and we do – but there is no legal obligation for regulators to pass on information to us. We think that creates an unacceptable level of risk."

Any medical accidents resulting from this may lead to legal action and add to the NHS’s spending to settle compensation claims, which totalled £807 million in the 2008-09 financial year.