At a Managers in Partnership conference in London on Wednesday, Sir David Nicholson said the NHS is in ‘undoubtedly difficult times’.

Just one day ahead of the publication of the NHS Operating Framework for 2012/13, he said the NHS is beginning to ‘fall apart’ but it is still not clear what the proposed new structures in the NHS are going to look like.

He said: ‘I would judge that we are in the most dangerous time, in my experience, in NHS history.

‘On the one hand the old system is starting to degrade and starting to fall apart and we are unable to sustain some of it. But the new system is not up and running and we are not clear enough what that looks like.’

Sir David said the NHS Operating Framework for 2012/13, which is expected on Thursday, will give details about the total resources available for clinical commissioning groups (CCGs). It will also outline CCGs' management cost allowance, he said.

It will also set out how much money the National Commissioning Board, Public Health England and local authorities and will be handled, he said.

Editor's blog: CCGs need clarity about management allowances from NHS Operating Framework