The two tribes of politics, broadly the Tory and Labour parties divided over the 20th Century principally on the matter of economics. Simplifying: Tories preferred market solutions to state planning, and preferred lower taxes and less generous state spending.
The Labour party, which when it abandoned clause IV, surrendered on the economic question, not coincidentally a few years after the Berlin wall came down.
As a result, the great battles since then have been essentially cultural. Gay rights, racial integration etc. The confusion stems from there being no consensus within the Tory or Labour tribes on these issues. Plenty of Tories are happily socially liberal, many of the Labour tribe are socially conservative, especially when you look at voters rather than representatives.
Which brings us to the tribal division of Britain: class. The middle class: liberal, internationalist, universalists; vs a working class: authoritarian, insular and particular world view. The former is comfortable with diversity and immigration. The latter isn't. The former's kids live a long way from home, and move for work, the latters kids live in the same town and expect the work to come to them. The former don't speak to their neighbours, the latter care what their neighbours do and think. These labels are correlated roughly with, but independent of, economic status. It's possible to be middle class, in a local-authority home living on benefits, and working class, earning seven figures and living in a manor house. (Though it's likely these people's kids will change tribes)
There are elements of these cultures in all major parties in the UK, but the rest of us rarely communicate with people from the other tribe. The people you have round for dinner will most probably be from your tribe. Half the country holds its knife like a pen, yet none have sat round my table. When the two tribes meet, it's awkward. Those difficult bottom-sniffing conversations seeking common ground are easy to conclude when two members of the same tribe meet, and difficult when you meet the other half.
There have always been working class Tories, because much of the working class is as comfortable with the certainties of heirarchy as a shire Tory, and doesn't much care for this freedom and opportunity nonsense, preferring a better boss instead. And it's interesting to watch the Tories dangle the protectionism and insularity the working class has long demanded. Middle class labour fabians and the working class methodists have always sat uncomfortably together. Brexit has shattered that coalition, the labour party has been handed to the idiot socialists and will die, unless somehow moderates can oust corbyn before 2020.
Which brings us to the Tory coalition. The high-Tory have promised the old certainties back to the white working class. Meanwhile, middle-class liberals who make up most of the parliamentary party are distinctly uncomfortable with much of what is being done in Brexit's name, but will stick with the Tories, because they offer the promise of power, and however dreadful Brexit is, Jeremy Corbyn is worse. A new coalition is being forged between the Tory squirearchy, and the Working class based on nationalism, social conservatism and heirarchy, directly taking Labour's core vote. This is why UKIP, a working class movement that thinks it *is* the conservative party, apes the style of a country gent. The working class have always got on well with the Gentry, sharing sociailly conservative values. Both despise the middle class.
Brexit split the country down a line more on class values, split the country and handed it to the socially authoritarian party. Whether this is the new politics, with the Tories moving from being the middle-class party to the working class party, as the Republicans did after the war in the USA, or whether the middle-class will wrest back control over both parties in time waits to be seen.
I suspect unless May softens her tone, and thows some bones to the liberals, her coalition will only survive until there's a credible opposition. A more appropriate division of politics would be a ConservaKIP'ish alliance of WWC and high-tory squires, vs LibLabCon middle-class liberals. Therea May seems to be actively seeking it.
Over the Channel, Emmanuel Macron and Marine Le Pen exemplify this split. The candidates of the parties of left, Socialists; and right, RPR are likely to be eliminated in the first round. Macron is likely to win comfortably. His movement 'En Marche!' was only formed a year ago. There's a lesson for British liberals there.