The independence of NHS trusts might best be protected by converting them into charities, according to Sue Slipman, director of the Foundation Trust Network.
Slipman told the FTN conference in Birmingham on Tuesday that the organisation, which represents foundation trusts, was not advocating the move, but believed there should be a "rational public debate" on the idea.
"There is an argument that real autonomy will be achieved only if the hospital's whole asset base is treated in another way," she said. "It is possible that these could be managed within a charitable framework that protected them on behalf of the nation."
Foundation trusts were created five years ago to give hospitals more autonomy and control of their own budgets. However, some trusts are concerned about their independence now that the Department of Health has proposed to return them to direct NHS control if serious failures are highlighted - such as in the recent case of Mid-Staffordshire NHS Foundation Trust.
Slipman said she was particularly concerned that ministers might put pressure on Monitor, the independent regulator for NHS foundation trusts, to "de-authorise" certain foundation trusts.
A spokeswoman for Monitor declined to comment on whether foundation trusts should become charities, but she said there was no obvious legal means by which they could currently do so.
John Mohan, an academic at the University of Southampton and deputy director of the Third Sector Research Centre, which is based at the University of Birmingham, said there had been disparities in wealth between hospitals in the pre-NHS era because large institutions in affluent areas were better able to fundraise.
He said this pattern had been repeated when the NHS had started to put more emphasis on fundraising in the 1980s and was likely to be exacerbated if NHS foundation trusts became charities.
"To some extent the horse has bolted," he said. "But if you give more of a green light to charitable appeals it will encourage hospitals to devote more and more effort to fundraising."