How independent is independent?
This afternoon the Health Minister will get to her feet and present a statement to plenary on "the evidence underpinning the Longley report into health reforms".
It is down for 30 minutes. The opposition parties are already saying that's not enough to deal with the long list of questions they feel they need to ask. Those questions centre on a series of Emails, discovered yesterday by BBC Wales and made public thanks to a Freedom of Information bid.
Is this story damaging for the Welsh Government? Yes, it is.
because having read the Emails, the three opposition parties are united in condmening them and united in putting pressure on the Minister, a rare sight during this Assembly term;
most of all, because no-one is more keenly aware than Lesley Griffiths that if she's to persuade the Welsh public that she is right to get to grips with the services provided by their local hospitals, she needs to have their trust.
I've sat in conferences where she's made that abundantly clear, listened as she and NHS officials have spelled out the fact that perhaps politicians aren't always the right, most trusted, people to make the case for change and that ordinary NHS workers convinced by the government's plans and independent expertise are needed to persuade ordinary users of the Welsh health service that unless it is changed, it will collapse.
Trust in that independent expertise, then, is key. Just yesterday the Labour AM for Llanelli, Keith Davies, faced local people worried about what 'change' will mean for their local hospital. In his hand, ready to wave, according to an opposition AM also at the meeting, was a copy of Professor Longley's report.
To be clear, Professor Marcus Longley knows the Welsh NHS like the back of his hand. His expertise isn't in question, nor is the fact that he, as author, regularly contacted government officials to ask for data. They hold it, he needed it. How else could he sift through all the information he needed and come to his conclusion?
Any listeners to BBC Wales debates on the future of the health service - to which Professor Longley has regularly contributed - will have a pretty good idea where he stands on the need to centralise some services to deliver a critical mass of expertise. That's a view respected across party lines.
However, the problem arises, say the opposition parties - in the strongest terms - with emails in which Profesor Longley asks civil servants for "killer facts" and seems concerned that the "evidence as presented does not seem to be as incisive as we might have hoped". Who, they ask, is the 'we' in that sentence?
Why, they ask, did he ask the Medical Director of the NHS, a senior Welsh government official, for more data "to sharpen up the document and its impact in supporting the case for change" and why did the same official, Dr Chris Jones, tell Professor Longley that the document "needs to be more positive if possible" and set out a more "persuasive vision".
That stinks, say the opposition parties. It undermines the vital independence of the report. For "sharpen up" they read "sex up".
Professor Longley remains adamant that all he did was gather the information he needed. His report was compiled "without bias or influence".
But the main focus will almost certainly be on the Health Minister herself, who told fellow Assembly Members that his report - a key plank in the government's plans and whose working title, by the way, was "A Case for Change" - was "completely independent".
The Welsh Government say that all their officials did was to provide statistical and other information when asked and that they "did not seek to influence or amend" the report.
"The people of Wales have the choice of believing the evidence based research of an independent and respected academic, or more nonsense from an increasingly desperate opposition. It will be no contest".
No contest? We'll see.