The Last Thousand Days of the British Empire, by Peter Clarke

There has, over the years, been a slow but profound shift in how Britain's history in the 1940s is remembered: one which also alters, more slowly but more deeply, our entire view of the country's recent past, present and possible futures. Once, the big story centred on triumph in war, followed – inevitably, it was often implied – by the twin themes of social reform and

economic decline. Historians of the left focused more on the former, Conservatives the latter, but with a great deal of cross-party consensus, just as among the politicians.

Today, big-picture histories of the 1940s and since are less likely to see the birth of the welfare state as the greatest transformation, more prone to put the end of Empire at the centre. The change of perspective is not only justified but overdue. Welfarism was very far from being uniquely British, and partly reversed since the 1980s. Britain's decolonisation was far more singular, far more important on a global scale, far less reversible. True, the old story can still be retold, even to dazzling effect, as if nothing that happened outside these islands mattered much, as in David Kynaston's brilliantly vivid but oddly myopic Austerity Britain. For that matter Peter Clarke, Cambridge professor of modern history and among the most eminent chroniclers of Britain's 20th-century political life, has always given his work a mainly domestic focus.

The Last Thousand Days..., with its Empire-wide and indeed global reach, signals an intriguing mutation in its author's preoccupations which reflects far wider British trends. Perhaps, though, it does not move quite so far from established patterns as its title, or the author's proclaimed intention, might lead one to expect.

The book has three great themes. First, that the ever-renewed debates over "what went wrong", why Britain declined after 1945, are largely irrelevant and misplaced. The die was already irrevocably cast (or in Clarke's metaphor, the cards all dealt) during the war years. The end of Empire, and Britain's effective subordination to the US, were made inescapable by the enormous costs of defeating Germany and Japan. Britain did not "win" the world war, but merely, and barely, survived it. At its end, the crises of indebtedness, overstretch and imperial retreat were preordained. "Virtually everything was worse than it looked" in 1945-6, Clarke insists.

The second big motif is Anglo-American relations, on which Clarke offers a sharply revisionary account. America's malevolent view of the British Empire doomed it. A principled anti-imperialism, at least as much as self-interest, drove the US policy which many in Britain saw as little better than a stab in the back.

"Power politics" was the standard 1940s American term of disapproval for everything they disliked about the way Old Europe, and Britain, operated – something amoral and supposedly distinct from the more idealistic US philosophy of international affairs. It all reads very ironically today; Clarke's view is obviously shaped by present-day concerns. In an age of US unilateralism, he has produced a reinterpretation of 1940s US policy that pushes close to seeing it also as unilateralist. The book is, in large part, a sustained attack on the myth of the special relationship.

The third crucial focus is, quite simply, Winston Churchill. He is not only the central character but – as the greatest symbol of the old imperial Britain – provides the common thread to its multiple storylines. In some ways, Clarke's picture of Churchill is notably harsh. Apart from his doggedly doomed, unrealistic, even childishly romantic, diehard imperialism, he is shown as cantankerous, clumsy, even downright lazy: as Prime Minister he rarely bothered to read Cabinet papers, and regularly reduced key meetings to rambling, sometimes drunken, monologues. Yet the Great Man is not entirely stripped of heroic stature. Clarke recognises that however flawed Churchill was, he was – in the worst days of the war – indispensable. The story of his, and Britain's, lonely, desperate, finally triumphant stand against tyranny has many elements of myth about it, but it was a necessary myth.

This is on some levels a bold and thought-provoking work, as well as a hugely enjoyable read. Yet in other ways it is surprisingly limited. Despite the title, only about a quarter is actually about the Empire as such. And that focuses almost exclusively on India, Palestine and the Dominions. Africa, southeast Asia, the Pacific, the Caribbean, or the Middle East beyond Palestine, are barely mentioned. Clarke focuses on his thousand days in 1944-7, and in narrating their events he is first-rate. His account of negotiations over India's future is among the best I have read.

He gives very little sense, though, of longer-term, strategic developments in Washington or London. The book's whole architecture therefore gives a slightly misleading impression, failing properly to register either how much British global power was already weakened before 1939, or how at least some British policy-makers were beginning to think about "transfers of power" from the 1930s – from the beginning, not the end, of the war.

Conversely, the presumption that with India gone imperialism too was dead is over-sweeping and simplified. It hugely underrates how "imperial" British thinking and strategies remained for decades after 1947; some would say, right up to the present. The effort to preserve a global role was longer-lasting and in some ways more successful than Clarke even hints. To say that after India, the "Big House", was gone, Britain's African and other colonies were no more than a "hobby farm", goes much too far – even if it is a venerable Cambridge view, first espoused by Clarke's former teachers Jack Gallagher and Ronald Robinson.

Stephen Howe is professor of the history of colonialism at Bristol University

Allen Lane £25 (587pp) £22.50 from 0870 079 8897

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