Chief executives at the trusts identified by the annual health check as the worst performing have hit back at the threat of takeover.

Health secretary Alan Johnson has asked NHS chief executive David Nicholson to hold urgent meetings with the four trusts rated weak in both quality of services and use of resources for the second year running.

'Stringent assessments would need to be made regarding the most appropriate course of action but one of the options could be takeovers by well-performing trusts,' he said.

Chief executives at the beleaguered trusts this week defended their performance, highlighting progress not reflected in the scores.

Northern Devon Healthcare trust interim chief executive Jac Kelly said her trust had made 'dramatic' improvements in the last year under intense scrutiny from the commission, the Department of Health and the strategic health authority.

She said: 'If there is more of that needed then we are more than willing to co-operate. But we think we have got the grip.'

Royal Cornwall Hospitals trust chief executive John Watkinson said it had also made great strides in its quest for 'long-term, sustainable improvement'.

Surrey and Sussex Healthcare trust chief executive Gail Wannell said change took time and that she would be asking David Nicholson 'to give us realistic but challenging timescales'.

She said the acute trust was planning to focus on its 'core business'.

'Where appropriate we will divest the primary care services we currently provide,' she said.

Professor Chris Ham of Birmingham University's Health Services Management Centre said takeover was not necessarily the best option and it would be more useful to look at ways high performers could support struggling trusts.