Set in a silver sea: the glory of Britain’s islands

Islands always intrigue, hovering on the horizons of our imaginations – seen, according to your lights, as territories to be taken, ancient redoubts, repositories of secrets, even loci of lands of youth. Where there are no islands, we often imagine them – Plato’s Atlantis, the Celts’ Avalon, the Irish Hy-Brasil, Zeno’s Friseland, Columbus’s Antillia – and occasionally find them, like Terra Australis Incognita, postulated long before Europeans made landfall.

Orkney was a trading station long before London, and Iona was the epicentre of Celtic Christianity

Britain was once itself an imagined island – or rather islands plurally, called by Pliny Britanniae, one archipelago among others in the great geographer’s speculative world atlas. Alice Albinia, the author of 2012’s highly regarded Empires of the Indus, now comes home to find all these Britannias for herself – the islands off this island nation, the offshore outcrops of this offshore outcrop.

She tells of islands elsewhere, but here her ports of call are Orkney, Anglesey, Wight, Iona, Thanet, Shetland, Lindisfarne, the Hebrides, Rathlin, Scilly, Man and the Channel Islands – and Thorney, where Westminster’s fanes first rose above brambles and reeds between Thames and Tyburn, and whose culture arguably still partakes of oozy mire.