What are the five fundamental British values? If you have missed that in your schooling, you can always go to a primary school in Brixton, talk to a Somali-heritage child and ask him or her to tell you. You are likely to get an enthusiastic answer. I have, on visits to the school where I am a Chair of Governors, not far from Brixton prison. And there is plenty of evidence from the children's parents that they think these values are a good thing.
The five values are: democracy, the rule of law, individual liberty, mutual respect, and tolerance of those with different faiths and beliefs. This formulation came from a Conservative-led government at a time of moral panic, when it was thought that immigrant communities were undermining our society. But it is, of course, the immigrants who are most enthusiastic about them.
There is a curiosity about these values. Looking at that list in isolation, would you think that "British" is the word that best defines what they have in common? Do these things make Britons different from Americans or Swedes, or even French? No. The common adjective that most comes to mind instead is "liberal".
Liberalism is under attack from many sides. A lot of people say that it means treating foreigners too well compared to your own people. Or that it stands in the way of effective government action. Liberalism is, in many people's eyes, middle class, elitist and Western, with a clear white ethnic character. It is a source of hypocritical lecturing by Westerners to people from countries that they have a long record of undermining or oppressing.
This is causing many people who hold liberal values as core beliefs a lot of angst - and I am among them. At various points I have suggested that liberalism needs to be rethought to break out of its white middle class ghetto. But I have struggled. My mistake is the usual one: I am over-intellectualising it. You might not think that appealing to Ludwig Wittgenstein is an antidote to intellectualism, but it was he who said: "Don't ask for the meaning, ask for the use". So just what is the use of liberalism?
At which point I remember my south London school. The school community is ethnically diverse (African, Afro-Caribbean and Hispanic all feature strongly) and predominantly working class. Why should they find liberal values so appealing? Or useful.
And the answer is clear. It forms a basis for people of different cultures to cooperate. And in such a diverse community people must cooperate in order to overcome common problems. And it also gives people the hope that they can get on in society based on their own merits. And, to many, it all looks a lot better than the state of things in the countries from where they draw much of their heritage - however proud of that heritage they are.
But Brixton liberalism is a much grittier and more basic affair than the Cambridge sort that I was brought up on. Many young girls wear the hijab in public; and the attitudes of many towards gays is probably best described as "toleration" rather than "embrace". But liberal values achieve real, positive, tangible things - literacy, numeracy and a more self-confident attitude to the world. Human rights means saving lives and stopping arbitrary torture, not just allowing prisoners access to cats (as our Prime Minister Theresa May once tried to suggest in an appalling speech while she was Home Secretary).
So why is liberalism so unpopular in swathes of our land, from the Daily Mail reading middle classes of Maidenhead, to the working classes of Doncaster? To them there is a better alternative: sticking together with their own group, and stopping other groups from having what they have got. These communities are not diverse, either ethnically or in terms of class. Or not as diverse as south London, anyway. To them liberalism just lets the foreigners in to walk all over them.
So is liberalism only useful to a middle class elite, who easily navigate the upper echelons of a liberal society, or to minority groups seeking to make their way against the odds? If so then it really is in trouble. Liberalism should be by its nature inclusive. If it is seen as exclusive, then it is in trouble. It isn't in Brixton. It is in Doncaster and Maidenhead.
So the challenge for liberals is to show how liberalism is useful to the besieged middle-classes defending their privileges, to the white working classes with insecure job prospects, or, for that matter, to tight-knit Muslim communities in Midland or Northern towns who feel their culture is under attack. And the first step towards that is to convince ourselves.
And here we can learn from Brixton. People there show us that liberalism isn't just about promoting a clever elite. It is about embracing diversity and about allowing everybody to get on in life. The world is being forced to change. It must face up to advancing environmental catastrophe, and the unavoidable march of technology. To do this the people of different nations and communities must work together. We must embrace diversity.
And there is something else we can learn from Brixton. Amongst the most positive things that a liberal society has done for this community is to provide them with good schools. In common with the rest of inner London, Brixton's schools are generally very good, notwithstanding high levels of disadvantage. and their ethos is unmistakably liberal.
If you want to see the use of liberalism it is easiest to do so in schools that are inclusive and help people to embrace the world more confidently. It's been said many times before, but that doesn't make it less true: you cannot beat a good liberal education. And there is no good reason why everybody in our society should not have one. That should be the loudest rallying cry from liberals.