The warning comes as private companies confirm they hope to run consortia if local GPs fail. Firms are also bidding to provide data the NHS Commissioning Board will use to performance manage consortia.

Dr Kambiz Boomla, a GP in east London and lecturer at London's Queen Mary University, said there was little evidence GPs would be able to balance constrained NHS budgets, and the DoH would replace them with private firms if they failed.

'A few years ago almost all PCTs were in financial difficulties and that was during years of growth,' he said.

'It seems odds-on that a number of GP groups will be struggling financially. If you marry that with the explicit pledge that the government will not tolerate failing organisations, groups will be either taken over by neighbouring groups or private organisations.'

Dianne Conduit, director of commissioning support at Humana, said the company would consider taking over consortia where local GPs are not performing.

'We can provide elements of the service or look at providing the whole package,' she said.

Firms have even expressed an interest in taking on some of the functions of the NHS Commissioning Board, which includes the performance management of GP contracts.

Tribal, which runs Ofsted inspections in the education sector, could perform a similar role in the health service, said its director, Kingsley Manning.

'There are a lot of functions like registration or data collection and analysis that could be done at that level by us or one of our competitors,' he said.

Dr Boomla said such a move 'wouldn't be out of place' with the current government's philosophy of 'opening up all levels of the NHS' to the private sector.

Mr Manning agreed that the DoH's decision to adopt an 'any willing provider' policy would open up NHS services to private firms 'to a new degree'.

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