Lustrum, the second volume of Robert Harris's trilogy following the life, career and political travails of Cicero, is a splendidly researched historical blockbuster of real human depth and political understanding: and if it were nothing but that, it would still be a fine achievement. But The Ghost, Harris's 2007 thriller à clef about a thinly disguised Tony Blair in American exile to avoid a war-crimes trial, made this writer's bitter dissatisfaction with the lies and cronyism of New Labour clear: and in his Cicero novels Harris has offered an even more involving portrait of the rise to power of a silver-tongued orator, impelled by a shrewish and cunning wife, whose moral idealism is perpetually threatened by military expediency, vanity and the demands of realpolitik. The reader may be forgiven for raising an eyebrow on learning that Lustrum is dedicated to Peter Mandelson.

Lustrum isn't just Westminster in Sandals: it’s a colourful novel about the politics of Rome, built around solid research and incorporating long passages drawn from Cicero’s own speeches and letters. But the temptations of power are timeless, and it is hard to make one’s way through Harris’s rattling