The Government is maintaining its line that ministers did not know about Mr Wintringham's involvement in questions relating to the doctoral qualifications claimed by Ms Thompson, and which are now subject to police inquiry.
She is said to have claimed she had a doctorate from the London School of Economics and Political Science, but the institution has no record of it.
Ms Thompson's lawyer, Helen Aikman QC, has since disclosed that the commission appeared to have been aware of the allegations for the past four years or so, "but they were not raised with Ms Thompson while she was a public servant".
A spokesman for the commission is reported to have confirmed that Mr Wintringham knew of the allegations, but that the information was not passed on to the new commissioner, Mark Prebble.
The Prime Minister, Helen Clark, has since said the commission needed to take a hard look at its systems to make sure relevant information was properly passed on.
But that is the very least of it.
As head of the New Zealand Security Intelligence Service, Miss Clark must know that this allegation goes to the very heart of the safety of government.
The reason is because all high-level bureaucrats likely to be or actually handling secret information must be subject to stringent "vetting", which is carried out by the SIS.
In Ms Thompson's case, such vetting would have been inevitable because for much of the past 15 years she has been at or near the highest levels of government.
She was a principal adviser to Winston Peters when he was deputy prime minister and Treasurer, deputy head of the Department of Prime Minister and Cabinet in both the Shipley and Clark administrations, and had at times been acting chief executive.
That means she was privy to the closest state secrets.
If, as appears to be the case, her principal economic qualification was bogus, why was this not identified when she was first vetted by the SIS? It is, after all, the simplest of checks: universities are well placed to confirm records of qualifications achieved.
The answer may lie in the way vetting is carried out.
The higher the likelihood of access the candidate will have to secret material, the greater is the depth of the vetting of the person and their background, including, where deemed necessary, personal interviews.
Obviously, the process is intended to identify security risks and the candidate's trustworthiness, but the SIS is only required to make a recommendation to the department concerned.
It does not itself decide whether or not to grant an individual security clearance.
It seems very unlikely the SIS would not discover the truth of Ms Thompson's claimed qualifications during this process.
There is then the matter of Ms Thompson's application in 2004 to be considered for the post of chief executive of the Department of Prime Minister and Cabinet.
It is is clear that her credentials were checked by a recruitment agency directed to assist Mr Wintringham to help fill the post.
Ms Thompson was at the time the acting head of the department and must have been considered to have an advantage over other potential candidates, having served in it since 1998.
It has been reported that she withdrew her application shortly after Mr Wintringham discussed the agency's finding with respect to her claimed qualifications with her.
This is the information Mr Wintringham did not pass on to the commission until very recently.
But why was she then enabled to be appointed to another high public service job, as a deputy secretary in the Department of Labour, no less, in charge of immigration? The Labour Department has said Ms Thompson did not claim she had a doctorate when she was appointed to the position.
One or more of the three inquiries now being carried out into this developing scandal may yet answer these mysteries, and Ms Thompson may yet produce a satisfactory answer herself to the claimed doctorate.
But if the vetting process is shown to have in any way failed to be sufficiently thorough, then what does that say about the standards of management at the highest levels of our government? At the very least, a shadow - a most unsettling and worrying shadow - has been cast across the whole of the upper echelon of the public service.
Trustworthiness lies at the very centre of all government administration.
Without it no elected government, and therefore no country, can function safely.
