There is a bookshop in Edinburgh called Grant & Shaw, which conjures images of Liz Shaw poring over some antique first edition only for Jo Grant to stumble in and spill coffee over it. And if you think that's not funny, it's still more humour than you're likely to encounter in The Wages of Sin, which relates the first joint enterprise of those two characters - and the Doctor, of course - and whose cover informs us that the contents are both "gritty" and "well-researched". One would expect no different from a David McIntee historical novel, driven by the impact of Rasputin's imminent death on Russian history. But when the author's note informed me that pre-revolution Russia still used the Julian calendar, I resolved that that particular well-researched factoid had better be relevant. Or else.

A problem with David's work is unattractive prose - as if his diligent research and the necessity of constructing a plot round it leave little time for the actual writing. Continuing the improvement most evident in his shorter Degrees of Truth, with this political thriller he has gone a long way toward addressing this and it transcends what I still see as unimpressive presentation.

Only occasionally does David's worst habit - untimely, unnecessary information dump - intrude. Characters interrupting their own plot discussion to debate the etymology of the Russian word for "railway station" is the most stunning example, and what remains infuriating about this is that it could so easily be avoided. However, though this does detract from the novel as a whole, there's no denying that the story is intriguing and the climax, in particular, is impressively tight - and David did catch me out several times when I thought I'd picked up on something unconvincing, such as the acceptance of a female scientist in 1916.

The calendar issue turned out to be unimportant as I'd suspected - but that seemed less annoying since against expectations, I quite enjoyed this book. Fans of David's work who find my criticism unduly harsh could consider how it might be improved yet further with severe, critical polishing.