My guess is that the GDS (Government Digital Service) has been swapping notes with folk at Microsoft about their
Metro "interface design language" (?) - the implentation of which can be seen, and no doubt admired, across recent MS GUI's.

As I mentioned before, less clutter. MS refer to the concept as "content before chrome", apparently. On which point I can only concur.
See here for more on Good Design (is it just me, or does it seem to be in short supply these days?):-
1) MS Design
Principles2) MS Modern
DesignAnd
Saul Bass - clever, no doubt (
sparse, even) - but perhaps not to everyone's tastes.