The Times obituary of Lord Carrington says:

More commonly, he found himself sleeping in a hole beneath his tank with his four crew who came from poor backgrounds and had suffered hardship during the pre-war years. The experience shaped his politics, he said later. "You could not have got a finer or better lot than they were. They deserved something better in the aftermath of the war.

This was a common sentiment. In exposing posh men to the working class, military service increased their sympathy for the poor - and as Adam Smith said, sympathy is the basis of our sense of justice. For this reason (among many others discussed by Walter Scheidel in The Great Leveler) the war led to big fall in inequality.

Herein, though, lies perhaps an under-appreciated social change in recent decades - an increased separation of the classes. I don't just mean geographic separation, though this is important. I mean separation in the workplace. Years ago, the classes would meet at work. In offices, posh men would meet less educated women in the typing pool: think of the Mad Men office. In manufacturing, middle class managers would rub shoulders with workers. And even in investment banks, there really were "barrow-boy"-type traders alongside old school tie-types.

This now is now longer so much the case. Many of us are in occupations where we only meet folk of similar class. And thanks to a lack of social mobility, posh people are unlikely too meet many from a different class origin. The only working class person a journalist might meet at work is the cleaner. For all the talk of diversity, many posh people now work in homogenous offices. As Daniel Cohen writes:

Only recently, workers, foremen, engineers and owners were connected by relationships that, though sometimes antagonistic, allowed each group to evaluate where it belonged in a shared industrial world. Now, engineers are in consulting firms, maintenance workers are in service companies, and industrial jobs are subcontracted, mechanized or relocated. (The Infinite Desire for Growth, p148)

I suspect this has contributed to increased inequality.

One obvious route is via increased assortative mating; middle-class men now marry other middle-class women rather than their (working-class) secretaries. That has increased inequality (pdf).

Another mechanism is the "out of sight, out of mind effect". If the poor never see the rich, they'll never appreciate just how great inequality is. For example, Sorapop Kiatpongsan and Michael Norton have shown (pdf) that in 16 countries, the ratio of CEO to workers' pay is massively greater than people estimate it to be.

By the same token, if the rich are out of sight, envy and resentment will be directed instead at the people who are in sight, such as benefit claimants.

But there's also the reverse Carrington effect: greater class separation means less sympathy and so less taste for redistribution among the rich.

One aspect of this consists of the othering of workers. Because posh people have so little direct knowledge of working people, they impute all sorts of bad habits to them, such as lack of aspiration, poor diet and racism - even though the latter especially is also found in posher people.

Such imputation also serves a reactionary function, as the belief that workers have "legitimate concerns" helps to popularize anti-immigration policy and to displace more radical agendas. There's just one problem with this. It's not true. Attitude to immigration have softened markedly in recent years (table 6 of this pdf). And in new research Matthijs Rooduijn concludes (pdf):

There is no consistent proof that the voter bases of populist parties consist of individuals who are more likely to be unemployed, have lower incomes, come from lower classes, or hold a lower education.

Ignorance of workers, then, might well contribute to both inequality and a misreading of politics.

All this said, things aren't so clear. Mere proximity to workers doesn't necessarily give you great knowledge of them: David Astor, the mega-rich editor of the Observer in the 50s, for example was shocked to discover that his staff had mortgages. Nor does it always generate sympathy. Perhaps the opposite. One reason for Thatcher's popularity among much of the middle class in the 1970s was that managers knew workers well and saw them to be lazy, bolshy and greedy.

All I'm suggesting is a possibility - that there has been increased separation of the classes since (say) the 1970s; that this might have political and social effects; and that all this is under-appreciated.