London's dark secrets

Through both his fiction and non-fiction, Peter Ackroyd has established himself as London town's most thrilling and imaginative chronicler, and in his latest novel he borrows Chaucer's pilgrims to tell a tale of 14th-century murder, mystery and intrigue.

Ackroyd's stamping ground is the East End, and he leads us through its maze of cookshops and fish stalls, alleyways and tenements, to the open fields that surround Clerkenwell's House of Mary, where Sister Clarice, a nun conceived in the tunnels beneath the convent, lies racked with visions of a fiery, apocalyptic future.

These are strange days, and while some hail Clarice as a prophetess, others believe the mad nun to be in league with earthly powers intent on overthrowning Richard II and installing Henry Bolingbroke on England's throne. Meanwhile, a male sect fantasises about the Last Judgment, encouraged by another more shadowy group, whose agenda is less religious than political.

The wealth of specialist knowledge that Ackroyd wields so matter-of-factly is as impressive as ever, illuminating every aspect of daily life, from the food his characters put into their mouths to the words and songs that flow from them. Harness it all to a suspenseful adventure story teeming with spies, idealists and secret societies, and the result is historical fiction of the utmost potency.