NHS England warned on Thursday that rising costs and projected slow growth in funding mean the health service faces a £30bn funding gap by 2020 - on top of the existing £20bn 'Nicholson challenge' efficiency target.
A discussion document published by NHS England, The NHS belongs to the people: a call to action calls for an 'open and honest debate about the future shape of the NHS'.
The NHS will have to change to face up to rising demand, adopt new technology and meet patients' expectations, the report says.
NHS England chief executive Sir David Nicholson said: 'The NHS was set up to provide high quality care for patients, free at the point of need. The NHS has stayed true to this aim and to do so in the future, we must embrace new ways of working.
'I am clear that our future must be about changing, not charging.'
Sir David said CCGs could find local solutions to reduce NHS costs, warning that the £30bn shortfall 'cannot be solved from the public purse but by freeing up NHS services and staff from old style practices and buildings'.
But BMA chairman Dr Mark Porter said NHS reforms had undermined clinicians' ability to deliver savings. 'The government has spent two years forcing through an unwanted reorganisation instead of giving the service space to address the funding crisis,' he said.
Dr Porter added: 'Doctors care deeply about patient care and more want to be empowered in order to make the necessary changes but are being held back by increased red tape and lack of support from the top.'