A quick paced, enjoyable, adaption, that ensured this story was already a firm favourite of mine long before I got the chance to see the episodes.
There are a lot of very visual sequences of the story, that still work well on the page. The opening chapters especially manage to convey an eerie and spooky atmosphere, in what might otherwise have been dull descriptions of bland scenery (the concrete and cables of the London Underground, and the mundanity of stations, are hardly the most stunning of vistas) ladling on shadows and making the most out of the spectral webs and fogs spreading through London.
The private museum, especially, benefits from a Hammer-esque atmosphere, that remains taut, even as great heaps of backstory are ladled onto us, with all the subtlety of a JCB.
The alien nature of the Intelligence is effectively portrayed, with the question of who can, and can not, be trusted, and who might be under the influence, a much more effective menace than the physical dangers of the robot yeti.
It is not a perfect story, but it is well written, and although some characters are drawn in broad strokes, and a little stereotypical, some effort is made to make them feel well rounded, and believable, if not realistic. The action rattles by at such a pace, that the flaws are more likely to be noticed after you have stopped to think, than during the reading.