A quarter of the world was once coloured pink, yet the story of the empire on which "the sun never set" has been written out of our national history, according to historian Professor Niall Ferguson.
Now, he says, the time has come to reinstate Britain's imperial past at the heart of the school curriculum.
Speaking to a specially invited audience at the second Prince of Wales summer school for English and history teachers, Professor Ferguson described the empire as "the big story of British history in the modern period", one which could even become the main organising theme for secondary courses Professor Ferguson has already been attacked for his Channel 4 series Empire - How Britain Made the Modern World and the accompanying book. He was accused of right-wing bias for presenting many aspects of the empire in a positive light.
Suggesting that imperial history should be a staple of classroom study could prove more controversial still. But Professor Ferguson countered the expected criticisms by insisting that understanding the history of empire history does not mean promoting "battles and tales of derring do" or glamorising British rule abroad.
"It's not all Baden Powell," he said. "Instead it is a mixture of economic, social and political history which would put contemporary British society into context. A study of Britain's involvement in slave trading, for example, makes little sense without the empire.
"There's quite a good case for the British Empire for teaching a broad sweep of history in a way that's attractive to children of all ages, from age 10 through until school-leaving age," he said.
He accused university history departments, even at Oxford where he taught till last year, of responding to national unease about the imperial legacy by ignoring the subject for the past 30 years.
Last year Professor Ferguson and other historians complained that too many students arrive at university with a fragmented view of the past and little over-arching sense of narrative. In particular, too much time was spent studying 20th century dictators, they said.
This week he suggested that the imperial story could be the answer. It would cover a broad sweep of history - home and abroad - from the 17th century to the present.
Teachers responded warmly to Professor Ferguson's proposals, but pointed out there was little chance of expanding a subject that often gets only one hour a week.
Pupils' historical ignorance was now affecting subjects other than history, said Cambridge English don William Poole. The lack of historical grounding among university literature students had become an "embarrassment", he said.