It’s been a hard slog but three years into the Labour government – the first for more than a decade – the chancellor stands up at a union conference to announce: success.

“Income tax and surtax going up to 95p in the pound has meant there are only 70 people in this country today with more than £6,000 they can spend out of income,” he says. New rules on what the rich can claim against tax “will further curtail luxury expenditure, as will the special levy”.

The speaker, of course, is not John McDonnell. It is Sir Stafford Cripps and the time is not the 2020s but 1948. Cripps, chancellor in the Attlee administration, made the speech to the engineering unions conference that year. The text, newly rediscovered by professor Bill Cooke of York University, is a reminder that inequality did not disappear spontaneously in the postwar period. It was actively suppressed.

Labour’s problem then was that Britain had lost its empire and was facing the first of the “balance of payments” crises that would haunt chancellors from then until now. Cripps needed wages to rise more slowly than prices – and the sweetener was the attack on inequality.

Cripps told the unions he had sliced £580m off income tax payments for the poor, and extended the social wage by £800m – half of it in the form of food subsidies. Given that nominal GDP for that year was £12bn, the scale of this redistribution programme came to more than 11% of GDP. “Then,” added Cripps with a flourish, “we are taking steps to reduce profits.”

It is a programme to make Corbynomics look positively Thatcherite by comparison. A rough modern equivalent would involve today’s government spending £61bn on food subsidies alone. Yet Cripps and his generation were cutting with the grain of history.

The top 1% in Britain saw their share of income fall from 22% in the Edwardian era to 10% by the time Attlee lost power in 1951 – and most of that fall took place under Conservative governments. The postwar welfare state, together with rising real wages once the boom took off, would see the 1% income share fall to just above 5% by the time Margaret Thatcher took office.

Now, it’s back at 15% and rising, according to research by Sir Anthony Atkinson, the UK’s leading authority on inequality. It has been driven not just by the rising salaries of CEOs and finance people, but by the switch from profits to asset wealth encouraged by governments of all stripes. If you bought a house in the London borough of Hackney 10 years ago, you will have seen its value double. If you’re obliged to pay rent on that house today, you are probably paying five times what you would have paid 10 years ago. The winner in both cases is the asset owner.

So what can we do? The first part of the answer is to understand the negative effects of inequality. Atkinson’s book, Inequality, published this summer, spells them out.

First, inequality punishes the unlucky. Lose your job and you are thrown back on your savings. Split up with your partner and you are thrown back on a single wage. If there is a reliable safety net of out-of-work benefits and social housing, personal catastrophes like this are survivable. Without them economic life becomes a lottery.

Next, inequality blights opportunity. Atkinson shows how being rich, or comfortably off, aids your ability to play the complex non-economic game. For a bright teenager, with guaranteed A*s upcoming, getting a train to Cambridge to see what it might be like still costs money. So does getting the tuition you might need to pass the additional entry exams some colleges impose as a kind of unspoken filter on the hoi-polloi.

Above all, inequality blights economic growth. We are living right now through an asset boom where social housebuilding is in crisis but there is money aplenty to throw up towers of luxury apartments along the Thames. Building these towers boosts the GDP statistics, and will allow football players, crooks and despots the world over to invest in the UK property market. But it is dysfunctional for sustainable economic growth.

What would be functional is to build 200,000 council or housing association homes each year. But we don’t do it – because, on top of all the other advantages, the rich have one more. They have a disproportional influence on policymaking. They can pay for lobbyists but, above all, they can tap into the networks that have begun to congeal around wealth in this country as it becomes quasi-hereditary.

Cripps makes a poor role model for the modern chancellor. An austere christian moralist, he seemed to revel in inflicting pain. He imposed rationing with zeal, not just on the moneyed classes but on the workers, whose demands for higher pay he pillories in the rediscovered speech as playing into the hands of Russia.

But both Osborne and his Labour shadow should be concerned about persistent inequality. It is, as Thomas Piketty suggests, built in to a form of capitalism where asset prices rise faster than profits, growth or wages.

Cripps, in his 1948 speech, demonstrates one principle very well. Suppressing inequality is not, in the short term, an easy sell. The rich, of course, lose income, profit and influence. To achieve a fall in the 1%’s income share in Britain would depend not, first of all, on this or that policy, but on achieving consensus on the need to do it, if possible across all parties.

Atkinson has proposed a 15-point plan to suppress inequality, at the centre of which is the idea of a “Social and Economic Council” involving employers, unions and NGOs, a living wage, a guaranteed income and the shaping of technology policy towards redistributive goals. The beauty of this is that, unlike the rest of Corbynomics (as outlined up to now), it stands a chance of achieving cross-party consensus.

Paul Mason is economics editor of Channel 4 News. @paulmasonnews