Now here's something that doesn't happen every day. A former Conservative prime minister and a former Labour prime minister delivering speeches condemning social inequality on the same day; inequality they were arguably instrumental in creating.

Meanwhile, the Tory-dominated Commons Work and Pensions Committee joined the unelected House of Lords in attacking George Osborne's tax credit cuts. Has the British establishment suddenly developed a conscience, or is something else going on?

John Major actually admitted that he had failed in his efforts to ameliorate “shocking” inequality. He delivered a warning: “Inequality is corrosive. It alienates and breeds resentment. It undermines national cohesion. The human spirit can endure great hardship but inequality gives it a bitter edge”.

Across at the Child Poverty Action Group, former Labour prime minister Gordon Brown made one of his rare interventions on a similar them: society was fracturing and it was time to end the demonisation of those on benefits.

He pointed out that more than half of Britain’s poor, 51 per cent, are in working households. Two out of every three children in poverty are in a family where at least one parent is in work. Mr Brown and Mr Major both dismissed the popular notion that a lazy underclass is “living off the state” as a lifestyle choice.

But this is the rhetoric of Mr Major's Tory party colleagues, particularly by Mr Osborne who managed somehow to turn the 2008-12 financial crisis caused by the banks into a welfare crisis caused by “skivers”.

He famously condemned the workshy who linger in their beds “sleeping off a life on benefits” while the hard working “strivers” set off for work in the morning. David Cameron talked of “the drug-taking layabout who embodies everything that is wrong with the welfare state”.

And it wasn't just the Tories. Former Labour Chief Secretary to the Treasury Liam Byrne, told his party: "Let's face the tough truth – that many people on the doorstep at the last election felt that too often we were for shirkers, not workers.”

As a displacement strategy for the financial elite, scapegoating the poor worked. Voters seemed to prefer to victimise poor people than hold to account the hedge fund plutocrats awarding themselves extravagant bonuses despite, having nearly wrecked the financial system.

That's why there has been a proliferation of poverty porn programmes such as Benefits Street. Nothing glues viewers to their sets better than undercover exposes of how the system is exploited by corrupt employers and devious benefits cheats.

Yet as Mr Major conceded out in his Hinton lecture, the vast majority of those out of work are unemployed not out of choice, but because there are few secure jobs. Britain is moving to a low-wage economy marked by heightened insecurity with many workers alternating between poverty benefits and poverty occupations.

Jobseekers allowance is so low at £73 a week (£58 if you're under 25) that it is impossible to live on, which is one reason very few of the able bodied are on long-term benefits. But, as Mr Major also pointed out, the real scandal of the benefits system is that most people claiming it are actually employed. He offered few solutions other than education. He argued that taxing the rich was no answer and suggested charities needed to provide a better safety net.

Which is where Mr Brown came in, defending his solution to the problem of poverty pay: the much-maligned tax credits. He argued that the whole point of tax credits, which he introduced as chancellor in the late 1990s, was to keep people in work rather than languish on the dole. It was to make work pay.

To be fair, it did, for many workers who would otherwise have had no incentive to go out to work. However, as tax credits expanded, employers realised this was a great way to subsidise their wage bill at public expense.

This is where we get to the root of the problem; not just of the crisis in the benefits system but of the economy as a whole. The balance of power has swung too far against labour and in favour of capital.

The share of national income going to wages has been falling for three decades. With the decline in trades unions, and the rise of automation, it has become much harder for workers to secure their fair share. Wages have languished leaving the state picking up the bill for poverty pay.

And it has to be said that Tony Blair and Gordon Brown are partially responsible for this through their “flexible labour market” policies. When he was chancellor, Mr Brown did little to stem the decline of manufacturing industry which he lamented in his speech yesterday.

Indeed, he famously celebrated the financial services sector and introduced the “light-touch” regulatory regime in the city which became the “soft touch” when the busted banks were bailed out with £1 trillion of taxpayers' money.

Mr Brown also held it to be self-evident that governments shall not raise personal taxes. But the inequality which is now rightly being condemned by former prime ministers of right and left cannot be addressed without using the tax system.

He is right that the tax credit cuts must be halted. But the political classes must turn their attention to the iniquities of a system that, under his watch, led to the absurdity of office cleaners paying a higher rate of tax than company directors.

An ever-increasing proportion of the wealth generated by society goes in profits funnelled either into tax havens abroad, property or the stock market. This cannot be allowed to continue or the low pay-low productivity spiral will continue.

And this is not simply the preoccupation of “left” economists such as Thomas Piketty. The Economist magazine agrees that technological change is undermining the economic security of the middle classes as well as the poor. As more white-collar jobs become automated, they are being squeezed as never before.

It may be that the current row about tax credits is something of an historical turning point in public attitudes to inequality. Voters are beginning to see the consequences hitting their families, especially the “millennials”: the young families who, Mr Brown pointed out, are being especially hard hit by high rents, impossible mortgages and stagnant wages.

More of Britain’s “hard working families” are finding they are slipping into genteel poverty. One-nation Tories like Mr Major are perhaps sensing that this is becoming a threat to the Conservatives at the next General Election.

Mr Brown's acute political antennae may also have detected a sea change in the public mood. Indeed, the Corbyn phenomenon in his own Labour party is a manifestation of it: a refusal to accept the logic of austerity.

Market capitalism is a most productive and adaptable economic system but every so often it needs to be saved from itself. It is time for the fruits of its productivity to be spread a little more widely.