Night Watch by Terry Pratchett

A slight softening of the funny bone

Things have gone very badly for Terry Pratchett in recent years. His Discworld series – of which this is the 27th instalment – has sold in massive quantities around the world; heavyweight critics, notably AS Byatt, have begun praising him for his "primal" storytelling gifts; and this summer he won his first mainstream award (the Carnegie Medal, for his children's book The Amazing Maurice and His Educated Rodents).

Things have gone very badly for Terry Pratchett in recent years. His Discworld series – of which this is the 27th instalment – has sold in massive quantities around the world; heavyweight critics, notably AS Byatt, have begun praising him for his "primal" storytelling gifts; and this summer he won his first mainstream award (the Carnegie Medal, for his children's book The Amazing Maurice and His Educated Rodents).

No doubt all this is highly satisfactory for his sense of self-regard; but such success has its own hazards. It may be that Pratchett has already come down with one of the gravest afflictions a writer can suffer: he has begun to take himself seriously. The symptoms are undeniable – unhealthily swollen books (The Truth came in at over 400 pages), a slight but noticeable softening of the funny bone, together with a hardening of the issues. Recent books have tackled political spin (Carpe Jugulum), press freedom (The Truth) and the nature of time (The Thief of Time).

Night Watch takes up that theme again, combining it with the relationship between law and justice. Samuel Vimes, the pragmatic copper who runs the City Watch in the Discworld metropolis of Ankh-Morpork, is accidentally whisked back 30 years into the past, where he is forced to act as mentor to his rookie self.

Matters are complicated by the presence of a murderous psychopath named Carcer, an adversary from Vimes's future, caught up in the same timewarp, who is swift to realise the potential for future havoc in messing about with the past. What's more, Vimes knows that events are leading to the Battle of Treacle Mine Road, a bloody confrontation between protesting civilians and trigger-happy troops. Is it his duty to avert tragedy, or to keep history on the right track?

Surprisingly for Pratchett, Night Watch gets off to a scrappy start and takes some time to gain momentum. There are, in line with recent trends, fewer jokes per page than in earlier books, and some are laboured. The sections in which the Monks of History explain the nature of time have a clunking, obligatory feel – you sense that Pratchett regards time paradoxes as useful apparatus, and is more interested in getting on with the story. Slightly tougher editing would have been welcome.

Once under way, though, the plot picks up momentum; the comparative shortage of quips is probably a help. And there is still room for some nicely thrown-away gags, like the gravedigger with the unusual forename of "Legitimate". "Can't blame a mother for being proud," one character remarks.

What makes the book intriguing is Pratchett's Chestertonian common-sense morality. While his blunt logic doesn't always equip him to deal with the niceties (at one point, he seems to argue against any controls on gun ownership), it allows him to break through liberal confusions and conservative certainties. His account of the Battle of Treacle Mine Road would be useful reading for anybody who holds strong views either way on Bloody Sunday – Pratchett's being, clearly, that stupidity is always a decisive factor in human affairs. His current condition may be serious, but it is a long way from being fatal.