Lang points out (page 15), an ongoing history of people whose loyalties - a religion or communism, for instance - override the state. And religious extremists are not the only ones trying to seek immutable truths in a confusing modern world.
In the uncomfortable, uncertain Britain of today, it is not surprising readers of the Telegraph should look to the past for comfort. They are raising money to send a copy of Henrietta Marshall's 1905 children's book Our Island Story to every primary school. The book tells a romanticised and, as the author herself made clear, mythologised version of British history. The Telegraph's urge to turn back the clock, eschew post-colonial angst and foster an idealised national identity is - as the authors of 1066 And All That, which spoofed Our Island Story, would put it - Romantic but Wrong.
Schools could only use such a book to teach about how people in the past viewed history, not to teach actual history.
But the impulse to reinforce British values and a national identity is worth thinking about. While it would be Repulsive and Wrong to return to the overconfident superiority of 100 years ago, perhaps we need to feel more comfortable with who we are and what we believe in. It has been suggested some young people from immigrant backgrounds look abroad for an identity because the British are too diffident about their own. Schools in all countries forge and reflect national identity. Schools in Britain promote values they can be proud of: tolerance, respect for other people and their cultures, community cohesion. This approach has clearly not worked for some young people who have been through our school system. But that does not mean it is wrong. Schools should hold fast to what they believe.