The GMC's workload has increased dramatically over the past 10 years, with the number of annual hearing days increasing from around 90 a decade ago to 1,992 in 2007.
Dr Peter Schutte, the MDU's head of advisory services, said that there had been a five-fold increase in the number of complaints made against doctors over that period.
As a result, it is not unusual for doctors to wait over a year before their case is heard. 'These delays have a devastating effect on doctors' lives, because they're aware that any case before the GMC could affect their livelihood,' he said.
The effect can be particularly harsh on junior doctors and locums, who often struggle to find work until a case is resolved. 'It's so unfair, because the majority of complaints don't go anywhere,' Dr Schutte added.
Sources say that the GMC's growing caseload has resulted from a growing awareness of expected standards of care, and a greater willingness to complain.
GMC figures suggest that the number of complaints made has risen by 24 per cent since 2003.
But a spokeswoman for the regulator said that, although the length of hearings has increased, the full process from complaint to conclusion had actually become slightly quicker in recent years.
In 2002, 90 per cent of cases were concluded within 16 months. Last year, 92 per cent finished within 15 months.
The spokeswoman gave several reasons for the longer hearing times, including more complex cases, more legal argument, and a statutory requirement to split the decision-making process into several parts.
Dr Schutte said that this longer process had brought advantages, such as focusing more on remedial measures than on punishment.
But he added that where once cases would be concluded in a two-day period, 'recently I've seen cases that drag on for years'.
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