That represents a loss of almost 4.5% of the active workforce.

Council members learned this week that the exodus of revalidation-shy doctors could leave a £2.5m hole in the regulator's finances.

To stop the gap, next year's annual registration fee is going up to £420, a 2.4% increase.

The fees increase will allow the GMC to hold on to what it considers 'prudent' reserves of £19m.

The cost of provisional registration is also rising to £145, bringing it in line with the fee for registration without a licence to practise.

The hike in fees follows a year of unexpected embarras de richesse when the regulator pocketed an £4m windfall from the scrapping of fees exemption for doctors over 65.

The GMC's 'healthy' balance sheet has been further boosted by a £3.4m underspend this year.

Professor Peter Rubin, GMC chairman, said: 'Doctors must have confidence that their regulator can deliver a high quality service at a reasonable cost. The modest increase in the annual retention fee is a prudent and sensible decision at this time.'

RCGP chairman Professor Steve Field said: ‘We haven't yet seen the figures but we've got to get the message out that revalidation is about professional development, not punishment. We are working with the BMA and the GMC to ensure that the proposals adopted are appropriate and non-threatening for GPs working hard to provide high quality care for their patients.'

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