The British Empire, the East African Chronicle wrote in 1921, was a ‘wonderful conglomeration of races and creeds and nations’. It offered ‘the only solution to the great problem of mankind – the problem of brotherhood. If the British Empire fails, then all else fails.’ Stirring words – and not those of some sentimental Colonel Blimp back in London. They were written by the newspaper’s editor, Manilal A. Desai, a young Nairobi-based lawyer and a prominent figure in the large Indian community in Kenya. But, as Matthew Parker observes in One Fine Day, an ambitious account of the empire at the moment of its territorial zenith on 29 September 1923, Desai’s encomium came with a caveat:

Either the British Empire must admit the equality of its different people… irrespective of the colours of their skins and the place of their birth, or it must abandon its attempt to rule a mixture of people. There can be no half way.

Parker’s narrative begins with the sunrise over Ocean Island, now known as Banaba, in the Pacific. The place was a rich natural source of phosphates, a vital ingredient in the fertilisers needed to realise the agricultural potential of other parts of the empire, most notably Australia and New Zealand. But to access the phosphate, the island’s own fertile soil had to be destroyed. It was, he writes, ‘extractive colonialism at its most literal’. He then follows the sun westward, through Australia, Asia and Africa to Jamaica.

Desai’s words proved prophetic, but the equality they argued for wasn’t necessarily quite what we think it is. Many in his community believed that Kenya should be annexed by India. East Africa, the Aga Khan had written in 1918, was ‘a free field for India’s civilising mission’. The question Desai raised was a good one, nonetheless. Who was the empire for? Did it exist merely to fuel the engines of commerce or did it have a higher purpose?

Some imperialists sincerely believed the latter. Trusteeship was, Parker writes, the ‘big idea’ of the moment: it was Britain’s role to nurture primitive peoples until they were ready to govern themselves. ‘The only salvation for the Malays,’ wrote Sir Hugh Clifford, a long-time colonial official in Malaya, ‘lies in the increase of British influence, and in the consequent spread of modern ideas, progress and civilisation.’ Even Leonard Woolf – an ‘anti-imperialist fanatic’, Beatrice Webb said – thought it out of the question to ‘leave these non-adult races to manage their affairs’.

Education, meanwhile – what Chinua Achebe would call ‘the white man’s knowledge… a collective aspiration of the entire community’ – was one of the grand bargains of imperialism. But was it wise politically? The Malays, another official said, should be taught only ‘the dignity of manual labour, so that they do not all become clerks’. Such a policy, he added, would avoid ‘the trouble which has arisen in India through over-education’. On the Gold Coast, according to its governor, there were too many semi-educated people who ‘knew just enough… to talk loudly about rights and other ridiculous things’.

Inevitably, Parker has had to be selective. He notes, for instance, the outrage felt in the Muslim community in India at the dismemberment of the Ottoman empire, the only great Islamic power, after the first world war; but he largely sidesteps the new territories, including Iraq and Palestine, that Britain gained through it. What vindicates his choices is the immediacy of his narrative, which is richly peopled and packed with incident and argument. While the book will be read primarily as a history of empire, it is also necessarily a history of anti-imperialist political organisation – and perhaps political consciousness. The sense one comes back to again and again is not so much of hatred or resentment but of an awakening feeling of betrayal.

Imperialism provokes strong reactions and One Fine Day may not change any minds. It isn’t trying to. But it should open them to the complex political and psychological realities of life under Pax Britannica for both the governed and the governing; and to the swirling currents of ethnic, social and religious identity that too many imperialists failed to understand because they insisted on applying the small, poor frame of what one Indian writer called ‘white-race supremacy’.

The British Empire had been a flexible, mongrel beast, adaptable to circumstance and accommodating of contradiction. But Parker’s book ends on a point not of equipoise but of exhaustion following the emotional and economic trauma of the first world war. Prior to the war, imperialism had been the dominant mode of government for much of the world. Yet with autocratic regimes once again on the rise, our present anti-imperialist moment may also pass. In which case One Fine Day may prove not merely history but a glimpse into our future, too.