"That means that Palantir software can only be used to process data precisely in line with the instruction of the customer. Using the data for anything else would not only be illegal but technically impossible due to granular access controls overseen by the NHS.”

I mean after you have analysed the data and gotten all the knowledge you need to get out of it, who the hell cares who owns the data. This only means you can't sell the data to other parties but you can still consult other governments, private health insurance companies etc for shit tons of money. I imagine most organizations would prefer the refined knowledge anyway since getting the data means they still need to process it somehow. Not to mention increasing chances of data leakage as you give more people unrestricted access to the data.

Why can't Palantir design the system and test it on some mock dataset or a portion of the dataset after which an engineer actually working for NHS tests the system on the whole data in an isolated environment that does not feed the data back to anywhere else. I thought their only role was organizational. Why do they need unrestricted access to the whole dataset so badly?