Doctor Who fans eternally cling to the sacred notion that the show will be rescued from limbo. Yet if it were resurrected, the new producers would find it stifling - not to say impossible - if they were forced to consider the wishes of all those fans. Crammed into the gap - such as it is - between The Massacre and The Ark, Salvation is constructed around a similar, if less narrow-minded, idea. Reduced to its basic premise as a didactic statement about the foolishness of either playing God or deifying others, it could seem unoriginal.

The potentially hackneyed notion of aliens impersonating gods begins to unfold impressively, though, the implications having been well thought through in terms of the diverse responses of the humans and the subsequent reactions of the aliens themselves. Perhaps Dodo's involvement relies a little on coincidence, but disregarding this, the early scenes are increased in effectiveness by the efficiently simple prose employed to convey how things are likely to develop, presenting a promising forward path.

Sadly, Salvation stumbles along the way. This is partly due to the abstruse origins and purpose of the aliens, but mainly because of the presentation. Most significantly, once the location shifts from London to America and events come under public scrutiny, the author fails to persuade the reader that any of it is really happening. Slickness and intermittent weak humour dominate the tone, to the extent that a plot with potential global significance and fairly spiritual themes comes across as a minor prank, and consequently the book falls short of the same author's The Witch Hunters in terms of emotional impact, despite even the apparently mandatory sadistic treatment of Dodo.

Although few of the people we meet are very interesting - with one particular familial relationship never developing into very much - I would have to admit that the revelation of the motives of one secondary character was beautifully executed. So Salvation is certainly not a total failure, but it's not the triumph the central idea deserved, and despite the promise of its first few chapters, redemption is ultimately not forthcoming.