Mutual Assured Destruction is a phrase I bet you'd forgotten. So had I until I read The Final Sanction.

Thankfully devoid of the mismatch of content and tone of Lyons' last novel Salvation, The Final Sanction is an unremittingly grim depiction of war. The Doctor, Jamie and Zoe are predictably ensnared because of the Doctor's naive lust for adventure, and as in The Roundheads, the Doctor must attempt to minimise the potentially disastrous effects of his own reckless actions on what is, to him, recorded history.

In a desperate conflict between humans and Selachians - shark-like aliens familiar from The Murder Game - the leaders on each side are xenophobically obsessed with security. For the powerful minority, peaceful co-existence is not desirable, and this story is essentially a fable condemning the exploitation of innocence by greedy cynicism. The Selachians are undoubtedly losing the war, and further conflict will have minimal effect - but nevertheless, that war has continued to escalate, with unnecessary casualties on both sides. A tone of despair, with polemic to the fore, is thus established. With Jamie injured in the conflict, and he and the Doctor powerless to effect change, an isolated Zoe has to take decisions concerning her personal responsibilities, similar to those facing the other protagonists.

Sketchy insights into those characters' upbringings purport to explain their apparent collusion in the carnage. Perhaps, though, it's rather facile to trace the development and current attitudes of each character back to one or two incidents in adolescence as Steve does here - that just gives everyone an excuse, undermining the moral issues raised, which are hardly original anyway.

However, while the eventual outcome seems inevitable due to the Doctor's foreknowledge, some of the supplementary information on the effect of events on particular individuals is kept in reserve, maintaining a welcome level of surprise, enhanced by the impressively depressing mood of fatalism which is the effect of the apparent predestination.

Given the subject matter, it's unsurprising that at times it's all overwhelmingly unrelenting and grim. Nevertheless The Final Sanction gets its point across effectively, despite a slow pace and somewhat heavy-handed moral tone.