From which country?” asked the ticket collector, the inevitable opener to any conversation in India. “England? You ruled us for 200 years. You should have stayed on and made us properly western. Now we are neither Indian nor British. I am from Gujarat, and I do not speak my own language.”

It is impossible to travel in India and not see the legacy of the British Empire. Mumbai - whose inhabitants invariably call it by its British name of Bombay - is an almost entirely British-built city, symbolised by the great ceremonial Gateway of India, originally constructed to welcome George V and Queen Mary but now a landing stage for tourist boats.

What is perhaps less immediately obvious is how the legacy of Empire explains so much about modern Britain. We speak in sweeping terms of “multicultural society” or “the Asian community”, airily lumping together peoples of vastly different cultures and backgrounds, in a way which the administrators of Empire never dreamt of doing.

The historian Patrick French describes meeting a family in Gujarat whose son was on a visit from his home in West Bromwich. His father complained:

“He tells me that in England they call him a Paki. Why do they do this? My boy has never been to Pakistan. Why would he want to go there? The place is full of Mussulmans.”

For many years German schools skipped the Nazi period and French schools avoided discussing the Algerian War. For British schools the black hole has long been the Empire. It went out of fashion in terms of teaching more or less when it started disappearing from the map, and it has never really crept back in. Its successor the Commonwealth, once the focus of such high hopes for the future, did not even merit a mention in the 1990 national curriculum in history.

Clearly, the main reason for this neglect of what remains a central feature of both British and global history was a sense of embarrassment. Some teachers preferred to apologise briefly for Britain’s having mismanaged a third of the surface of the globe before hurrying on to more genuinely multicultural topics from the pre-colonial history of Africa or Asia; others felt nostalgia for tiffin and pith helmets but didn’t dare say so.

The issue of Empire was revived by a number of academic historians from the 1990s onwards, but they did it in ways almost guaranteed to alienate most teachers. Thus John Charmley’s controversial 1994 biography of Churchill lamented the fact that Churchill had sacrificed the Empire in his zeal to defeat Hitler, and Niall Ferguson’s TV series Empire defied popular orthodoxy by arguing that Britain had much to be proud of in its imperial legacy.

Anthony Beevor’s call at the Prince of Wales’s 2003 summer school in Norwich for teachers to place the story of Empire at the heart of the history curriculum prompted a tentative textbook and some articles in the Historical Association’s journal Teaching History, but there is no sign as yet that history teachers are prepared to drop the Nazis in favour of British Empire.

There is a certain irony here. Hitler was an enthusiastic admirer of the British Empire, and he lapped up repeated showings of Gary Cooper in The Lives of a Bengal Lancer in his private cinema. The fiercely nationalist Hindu parties in modern India, the BJP and Shiv Sena, are open about their admiration for Hitler, and in Chennai I found you could buy enamelled quotations from Mein Kampf on the street. Important as the Nazi era undoubtedly is, it actually makes study of the Empire more urgent, not less.

In academic circles, the Empire has been making a comeback for some years now, and many postgraduates are attracted to sexy “post-colonialist” topics for their PhDs. Of course, most academic articles take a robustly anti-imperial line, revealing the failings or hypocrisies of British colonial rule; hence, of course, Niall Ferguson’s robust rejoinder.

The truth, however, is that study of the Empire will not fit neatly into caricature from either quarter. Europeans went out into the Empire for a bewildering variety of reasons, and the peoples they encountered responded in an equally bewildering variety of ways.

The first thing a study of Empire requires is to cast off all preconceptions and prepare to be constantly surprised.

Coming through Belgaum in Karnataka on the train I reflected on my own roots: my great grandfather was born there and both he and my grandfather died in Karachi. In any classroom in Britain a substantial portion of the pupils - and of the staff - will have Empire in their ancestry.

The Empire is what threw us all together and made us, Scots, Welsh and Irish every bit as much as the English, the highly complex people that we now are. School history helps to develop a sense of identity, but it is hard for that to happen if it misses out the Empire that created much of it in the first place.

Sean Lang is a research fellow in history at Anglia polytechnic university and honorary secretary of the Historical Association. Should pupils learn about Britain’s lost empire? Email your views to: letters@tes.co.uk subject focus: History, TES Teacher