About one in five doctors has had experience of an incompetent or poorly performing colleague within the past three years, a study has found.

But one-third of those questioned said they had failed to report the colleague to the relevant authority, leaving patients at risk. The survey of 1,000 doctors in general practice and hospital medicine in the UK compared their experience with 2,000 doctors in the United States.

Where doctors had not reported a colleague, the most common reason in Britain was that they were afraid of retribution, reflecting the unsympathetic treatment of whistleblowers. A recent British Medical Association survey found that 16 per cent of doctors who had reported a concern about a staff member faced a warning that it would affect their employment.

The most common action by US doctors was to stop referring patients to the colleague – an option not open to British GPs, who mostly refer to a hospital department rather than to a specific doctor.

One in five doctors in both countries disagreed that they should put patients' welfare above their financial interests.