The under-fire NHS boss has rebuffed calls for him to resign and said he "absolutely determined" to say in his job.
Sir David Nicholson said he wanted to he wanted to lead the NHS through coming health reforms, despite admitting failures over the Stafford Hospital scandal.
Sir David admitted that the "NHS lost its focus" and conceded that he "was a part of that".
But furious campaigners called for him to be sacked following the publication of the Francis Report into serious failings at Mid Staffordshire NHS Foundation Trust.
He was in charge of the regional health authority for 10 months between 2005 and 2006 - the height of the failings in care at the trust.
Giving evidence to the health select committee, Sir David told MPs at a cross-party committee that the local health authority had "no idea" about the serious care failures at the trust.
Patients were routinely neglected and as many as 1,200 could have died needlessly as a result of maltreatment and neglect.
Patients were left lying in their own urine and excrement for days, forced to drink water from vases or given the wrong medication.
– NHS boss Sir David Nicholson
We had no idea.
The information was not bought to the strategic health authority, we did not see any of the information which would lead you to believe that there was all of this going on in Mid Staffordshire.
I had not come across hospital standardised mortality rates during my period at Shropshire and Staffordshire nor before that.
I did not have access to that information. At that moment in time, surprising as it may seem in retrospect, it was not part of the regular way in which NHS organisations were monitored in the NHS.
But campaigners said the NHS boss should not stay in the job.
Deb Hazeldine lost her mother, Ellen Linstead, in December 2006 after she caught a superbug at Stafford Hospital.
She told ITV News it was "unacceptable" that Sir David Nicholson remains in his job as NHS chief executive following the Mid Staffordshire Hospital scandal.
Another branded him an 'absolute disgrace'.
Julie Bailey, who set up the Cure The NHS campaign group after her mother Bella died at Stafford Hospital in 2007, said Sir David's evidence was "shameful" and "embarrassing".
Asked about suggestions that he would stay in post to lead reform of the NHS, she said:
– Cure The NHS campaign grou founder Julie Bailey
That man is an absolute disgrace
I think it's just laughable. He is desperate to carry on in his job.
We need to get rid of him. Nothing will change. He is part of the problem, not the solution.
Sir David told MPs that he regretted not meeting with the Cure the NHS campaign group when the failings at Stafford Hospital came to light.
Sir David said that when he held senior posts in at Mid Staffordshire NHS Trust, he was unaware of the failings happening at the trust.
– NHS boss Sir David Nicholson
I had no idea...
As shocking as it is, that is the truth. It's not to say there wasn't any information around in the health care system before I got there and by other organisations. We did not, in the NHS, at that time, a culture of sharing information across the system.
But former Health Secretary Andrew Lansley gave his full support to under-fire NHS boss Sir David Nicholson as he arrived at Downing Street this morning.
He said: "I'm very clear that David Nicholson is somebody whose knowledge and commitment to the NHS is absolutely essential."
Asked what changes were required to implement the recommendations of the Francis Report on Mid Staffordshire Hospital, Sir David Nicholson said: "This is a significant change programme for the NHS from literally top to bottom.
"It's from setting out basic standards that patients and everyone can understand and assessing and inspecting again against them."