When I was a child in Lahore in Pakistan, my parents employed a driver called Sultan. Sultan, a retired soldier, was from a village near Jhelum. He was a cheerful man in his 60s who readily joined in our games of badminton. But to me the most interesting fact about Sultan was that he could speak Italian. A fragmentary, broken Italian, but Italian nonetheless, picked up as a prisoner of war in Italy. He called me signorina and taught me three Italian words: si, grazie and buongiorno. Decades later, when I told my children about Sultan, they were gobsmacked. What was a Pakistani villager doing fighting in Italy? He wasn’t Pakistani then, I explained, he was Indian. Sultan was one of more than two million Indian soldiers who fought for the allies in the second world war. “No! Really?” they breathed.

My children (daughter 17, son 15) were born and raised in London and have had the good fortune to attend fantastic schools where they have been offered, alongside the usual array of subjects, a rich diet of music, drama, art, sport and languages. Their extracurricular clubs include Arabic, feminism, astronomy, mindfulness and carpentry. In my convent school in Lahore, I had to listen in respectful silence. In London, they are encouraged to question and argue.

Yet, for all the range and candour of their education, they haven’t once encountered Britain’s colonial past in school. My daughter is now in her second year of A-levels. She has studied history from the age of nine, but the closest she has come to any mention of empire was in her GCSE syllabus that included the run-up to the second world war. While studying the Treaty of Versailles, she learned that some countries had colonies at the time and, as part of Germany’s punishment, it was stripped of its colonial possessions. Period.

Though she read about the brutal battles in the Pacific and North Africa, no mention was made of the 2.5 million Indian soldiers who volunteered to fight in the second world war – or the 1.3 million who served in 1914-18. There was nothing about the 87,000 jawans killed in 1939-45. She had no notion of the massive contribution India – and Britain’s other colonies – made to the war effort. Hence her astonishment at Sultan’s Italian connection.

Of course, my kids know that their grandparents, along with the citizens of almost half the globe, were once British subjects. But they have acquired this knowledge at home, not at school. Aged 11, my son learned in a geography class that one of the many reasons Ghana (the Gold Coast to its 19th-century British rulers) was economically less developed was because of its colonial past. It had been stripped of its wealth by the British. Just one bland sentence. Now, in secondary school, he is currently reading a past Booker winner, The White Tiger by Aravind Adiga. For half-term, his English teacher has asked him to read another novel about India. The list she has given him includes Rudyard Kipling’s Kim, EM Forster’s A Passage to India and Salman Rushdie’s Midnight’s Children. I imagine some mention of colonialism will be made when discussing those texts.

But even this is off-piste learning, the initiative of an individual teacher; it is not part of the curriculum. Last year, my daughter, who is studying history of art at A-level, was taken to see Tate Britain’s exhibition Art and Empire. Her teacher thought it important for the paper on orientalism and, something of a political activist in her youth, gave them an impassioned lecture on Britain’s imperial past. But the historical context was not obligatory in the curriculum. Students were required to restrict themselves to a technical visual analysis of the paintings they studied, not explore the political background that produced them.

Dr Mukulika Banerjee, director of the South Asia Centre and associate professor of anthropology at the London School of Economics, talks of British students who “arrive at university completely ignorant about the empire, that vital part of their history. When we talk of Syria today, they have no knowledge of Britain’s role in the Middle East in the last century. When discussing burning political questions today, they have no historical context to draw on that links Britain’s own past with those events. Similarly, they have no clue about the history of the immigration. They don’t understand why people of other ethnicities came to Britain in the first place. They haven’t learned any of it at school. So, in their second year at university, when my students discover the extent of their ignorance, they are furious.”

I don’t know whether this amnesia is due to embarrassment or fear of reparations or, indeed, a sinister desire to keep the electorate ignorant and pliable. Whatever the original rationale, the ugly xenophobia unleashed since the EU referendum has brought home the urgent need to reform history textbooks and address this abyss at their heart. Without it, they are distorted, dishonest. I used to laugh when British people asked me where I had learned my English. (Despite 20 years in this country, I still have a strong Pakistani accent.) Post-Brexit, I am not amused. And it’s no good pretending that the history of Malaysia, Nigeria, India or Kenya is world history and therefore not relevant to the modern British curriculum. It is British history. To quote Kipling, that controversial yet compelling poet of empire: “What should they know of England who only England know?”