The GMC's fitness-to-practise statistics for 2009 show that this accounted for the largest proportion of enquiries. This was followed by the ‘non GP/specialist' group (22%).

The report also showed that of all the fitness-to-practise hearings held in 2009, the largest proportion appearing before a panel were non GP/specialist (45%) and GPs (37%).

In total, 27 GPs were erased from the register at a fitness-to-practise panel hearing, the report outlined.

It also revealed that in total 270 fitness-to-practise hearings took place in 2009, compared with 204 in 2008.

The GMC said the increase is linked to an increase in the number of enquiries made from the NHS, police and other public bodies, which has risen significantly since 2006.

‘Referrals from these groups are likely to be more serious and therefore more likely to progress through to a public hearing,' the GMC said.

It said the most common allegation resulting in removal from the register in 2009 related to ‘improper relationships with patients', which accounted for 15 cases in total.

Paul Phillip, director of standards and fitness to practise at the GMC, said the GMC does not yet understand why there has been an increase in the number of serious concerns, and said research would be carried out to find out.

He said: ‘I'm afraid there are no hypotheses. We are not saying that we haven't thought about it, nor that we haven't chewed the idea over that it has something to do with revalidation, or something to do with licensing.

‘The reality is that we have absolutely no way in which we can say that's why it is. It is odd that there are more serious referrals, and they are appropriate referrals coming to us. It all started six or seven months ago, and there is clear trend., and that is why we need to get to the bottom of it. We have thought of the same things you have thought of [revalidation] but there is not a reason to suggest that that is the case.'