One of Nick Clegg's closest advisers has threatened to quit unless ministers make substantial concessions to a proposed overhaul of the NHS.

Lib Dem MP Norman Lamb said the plans posed a major "financial risk" to the NHS and patient care could suffer.

He said he would quit as Mr Clegg's chief political adviser unless NHS professionals were "on board".

Ministers have pledged to listen to public concerns, but insist the NHS cannot be allowed to stand still.