'It must be clinically and patient-driven, whatever its structure,' he told the NHS Innovation Expo in London this week. 'It has to have clinicians and outcomes at its heart,' he said.

The new board will not be split into 'tiers' or localities but will be 'one corporate body' to get consistency in outcomes', said Sir David.

Representatives of the board may sit on local authorities so the board has 'local connections', he said.

Responding to questions from the floor, the NHS chief executive said it was 'perfectly possible' some consortia would fail but he hoped that he would be able to intervene before they did.

Two thirds of the NHS Commissioning Board's £400m annual operating costs will be spent on commissioning primary care, dentistry and opthalmology, said Sir David.

The board's role in allocating budgets to consortia will be 'crucial' said Sir David. The board will be able to 'shift resources around the country' to help improve quality and spread best practice, he said.

Opening the expo, health secretary Andrew Lansley said the NHS should have a 'relentless focus on what patients want' like 'the best companies - Apple, Virgin and Tesco.'

'Every pay structure and incentive' would eventually be related to outcomes, rather than processes, he said.

Under questioning from broadcaster and conference chair Martyn Lewis, Mr Lansley admitted he sometimes felt anxious about his reforms. 'But you always do when you're doing something exciting,' he said.