Most GPs will be women by 2013, a two-year study by the Royal College of Physicians (RCP) found earlier this year.

Now the former RCP president, who caused a furore in 2004 when she said too many women doctors would undermine the profession's status, has gone further.

'We are likely to have 70 per cent women in our workforce in general practice, if not more,' Dame Carol told a Medical Women's Federation (MWF) meeting in London this month.

But 'detailed thinking' will be needed for part-time female GPs. NHS savings of £20 billion will 'hit us hard by 2011', Dame Carol said.

Part-time work is expensive and 'there will be core constraints on affordability', she explained.

'If we work part-time, there is a lower lifetime return on initial training and investment and more organisational complexity and overhead costs.'

Dame Carol said women doctors will have to make 'a business case' for part-time work.

But she insisted that part-time staff are no less professional or committed: 'It is essential that we stop any idea that working part-time means you are not delivering a professional service,' she said. 'It is important that women have the widest reasonable choice of work options.'

Forty-eight per cent of female GPs work part-time, the RCP study showed.

Dr Clarissa Fabre, a GP in Uckfield, East Sussex and MWF president-elect, said women work part-time 'in patches'. 'It is a matter of getting through a difficult patch, trying to be a good parent but also trying to achieve what you can in your career.'