We watched it and, making due allowance for the inevitable scene-setting and character-establishing that goes on in the first episode, we thought it had promise. Will certainly continue watching. McCrory and Laurie were excellent, I thought. Not so sure about the supporting parts (ie the Parliamentary wonks) who mostly seemed 2-dimensional.
We don't find this sort of drama suits us on a Sunday, though. It's more of a midweek thing for us, so we'll probably watch it a few days delayed, so no spoilers, please!