Black Robe, Brian Moore's last novel, and his first attempt at a historical theme, was a masterly exploration of the cultural abyss between the North American Indians and the Jesuit missionaries come in the name of God to "civilize" them. In The Colour of Blood the Jesuits again feature prominently and God is frequently invoked, but the time is the 1980s, the setting somewhere in the Eastern bloc (not Poland, although there are obvious similarities) and the style that of the political thriller.

Days before the bicentenary of the September Martyrs, an attempt is made on the life of the Catholic Primate, and the ensuing tension threatens to destroy the hard-won concordat between Church and State. The "raincoats"—as the much-hated Security Police are known—want to keep him in "protective custody", but he knows that his presence at the celebrations is essential to prevent a massive uprising. Shedding the red robes of his office for "the disguise of failure", Cardinal Bem goes on the run in a nightmarish world where even his own bishops are not to be trusted. Who are the instigators of this plot? Are they simple patriots, or right-wing fanatics backed by the CIA, or agents of a government fearful of that "larger neighbour" on its border and needing an excuse to stem the ever-growing power of the Church over the minds and hearts of the people? Only in the final chapters is the truth made clear.

The Revolution Script, Moore's imaginative reconstruction of the kidnapping, in 1970, of a British diplomat in Montreal, took us into the mind of the revolutionary left; in The Colour of Blood he invites us to consider the philosophical rather than the personal implications of political action. The thriller format becomes a vehicle to explore serious political and theological issues: the relationship between Church and State, the validity of "liberation theology", the meaning of "freedom" and "responsibility" under a totalitarian régime. In particular Moore questions the authenticity of a religious fervour too closely linked with political aspirations (the unstated parallels with the author's native Ireland spring first to mind, but the phenomenon is worldwide). Cardinal Bem personifies St Bernard's ideal of a man ruled by reason, balancing the demands of God and Caesar without ever losing sight of his priorities; in contrast, the Prime Minister, like Bem a graduate of the Jesuits, represents reason gone wrong, a leader prepared to countenance torture, detention, even murder, in the name of "the national good".

Always the consummate craftsman, Moore never allows the tension to slacken, reminding us that he is a writer who once worked with Alfred Hitchcock. From its opening sequence—a limousine speeding through the glistening streets of the capital towards the assassin's gun—to the spectacular finale in a cathedral glowing with candles and stained glass, this is a novel that cries out for cinematic treatment. Moore's prose is faultless, economical and elegant; and if the characterization is thinner than we have come to expect from the creator of Judith Hearne and Mary Dunne, it is only because it has been subordinated to more intellectual concerns.