Not at all as good as the first volume in the trilogy. This volume follows our British Communist Party supporting couple, Alan and Elsie Sebrill after the Second World War in the late 1940s. It documents the debates within the BCP about how far to support the post-war Labour Government. Alan and Elsie become increasingly disillusioned with the Party, feeling it is too revisionist and not sufficiently Marxist-Leninist. We are in pure Life of Brian territory here; the Judean Peoples Front and the Peoples Front of Judea (splitters). There is one moment when Alan is becoming very nervous about falling out with the party and says the word Stalin as a mantra to calm himself down; at once hysterically funny and rather sinister (probably not meant to be either). This is the far left as I remember it in the late 1970s; quite ridiculous, Spartacists arguing with Maoists, arguing with Militant, arguing with the Socialist Workers Party. Too much doctrine and too little connection with real life! There is however a very good description of a nervous breakdown as Alan and Elsie do leave the party which has been absolutely central to their lives. Upward here is describing how he felt when he left the party and you can tell it comes from real experience. Because it is a circular and self-contained belief system the logic is difficult to combat. There is a telling description of Alan and Elsie being called to see a senior member of the party; the argument "two and two make five whatever you say or argue". This didn't have the historical interest or the power of the first in the trilogy; but Upward still manages to write without hindsight.
Your tolerance for this might be conditional on how much you can bear the extreme and unwarranted self-importance of British Communism, but I for one was gripped by this mix of intense Proustian retrospection and intricate Marxist-Leninist bickering. One day there will be novels like this written by recovering veterans of Left Twitter.