The appeal of Palantir to the Civil Service is clear; it offers workable (and working) IT 'solutions' in an environment where too often IT projects have failed to deliver, but the problems with Palantir are two fold:
Its links to the Far Right (Peter Thiel is clearly an anti-democrat), leading to concerns about the firm being in control of so much UK vital data;
But if it wasn't Palantir, putting the state into hock with a large single provider is in itself ill-advised.