James Naughtie and readers talk to travel writer and literary critic Robert Macfarlane about his book The Wild Places, in which he sets out to discover if there remain any genuinely wild places in Britain and Ireland.

It is an account of journeys that he made to the remaining wilderness in the islands. He climbs hills and mountains, walks across moors and bogs, luxuriates beside hidden lochs, swims through caves and disappears into forests, all in search of that special quality of solitude in communion with nature.