Johann Hari: When will the soufflé of spin collapse?

I can't think of many other politicians who regularly give speeches demanding X while knowingly doing the opposite

David Cameron is leading Britain through a huge and unpredictable experiment. I'm not talking about his decision to impose massive cuts in the middle of a recession. That's not an experiment at all. We know how that ends. Look up the history of the 1930s Great Depression, or – as George Osborne once said – "look and learn from across the Irish Sea." No: I'm talking about a genuine test. The Prime Minister is trying to see how far you can separate your political rhetoric from your actual political action, before the entire soufflé of spin collapses. How long in politics can you say one thing and do precisely the opposite?

This week alone, the headlines have been dominated by three subjects where Cameron is doing the polar opposite of what he is telling the public. Let's look at them.

Deception One: The banks. The story of the Great Crash of 2008 is clear, and understood by almost everyone. Starting in the 1980s, the rules introduced to stop banks from gambling with our money were systematically stripped away. The politicians who did this – Thatcherites and their New Labour spawn alike – said bankers were perfectly rational beings, so there was no need to tie them up in "red tape" and "restrictions." Set free, they effectively took our money to Las Vegas and blew it all, then demanded we pick up the tab. The bill and the shock have broken the global economy.

After bankers crashed the economy in 1929, some committed suicide. After they crashed the economy in 2008, they demanded even bigger bonuses.

David Cameron told the British people before the election he was "outraged" and would ensure it "never happened again." He promised extensive re-regulation and that all bankers' cash bonuses in nationalised banks would be strictly limited to £2,000. Yet in private, he assured a closed-door meeting of senior City execs: "My father was a stockbroker, my grandfather was a stockbroker, my great-grandfather was a stockbroker." He hoovered up their donations so enthusiastically that half of the entire Conservative Party's income now comes from financiers.

In power, Cameron has served his paymasters, not his people. When the EU tried to restrict bankers' bonuses in line with Cameron's election promises, Cameron vetoed it. When the state-owned banks paid themselves bonuses of more than £2m with our money this week, Cameron approved it. It's appropriate that the conditions imposed in return for these bonuses are called Operation Merlin, since he was a mythical figure, and this proposal is full of them. For example, the banks only have to increase lending "should sufficient demand materialise" – a loophole so vague that senior bankers call it "meaningless."

But worst of all, when there have been international moves to reregulate the banks to prevent another crash, Cameron has scorned them. So it's all going to happen again. The US Treasury Department's Inspector General, Neil Barofsky, recently wrote we will "end up in a similar or greater crisis in two, or five, or ten years' time. It is hard to see how any of the fundamental problems in the system have been addressed to date. [The bailouts] saved our financial system from driving off a cliff in 2008, [but] we are still driving on the same winding mountain road, but this time in a faster car." Can you afford another crash?

Deception Number Two: The Big Society. It is unfair that people keep saying the idea of the Big Society is "incomprehensible" and "unclear." It's actually a clear proposition, articulated plainly by Cameron. It is the belief that as the state cuts back its services, volunteers will step in to provide those services for free. So you can stop paying the local librarians, or the local youth club, or the local museum, and local people will step in and run it themselves, for nothing. The state "crowds out" volunteers, and when it retreats, they come flooding back.

This is perfectly comprehensible. The only problem is that it doesn't match reality. To find out why, just look at the facts. The sociologist Amitai Etzioni conducted a major international study of volunteerism. He found that volunteering is highest where state funding is highest, and lowest where state funding is lowest. So high-tax Massachusetts has the most volunteers in the US, while low-tax Mississippi has the fewest. High-tax Sweden has the most volunteers in Europe, while low-tax Eastern Europe has the lowest. Far from "crowding out" volunteers, a big state attracts them, and a small state drives them away. Why? There are several reasons. A well-funded state can recruit, train and direct volunteers. And in a high-solidarity society, people are less panicked about losing their own jobs and more likely to trust their fellow citizens enough to want to give something back to them.

If Cameron had bothered to look, he would have known all this. If he had wanted to increase volunteerism, he would have increased the budget to promote and recruit volunteers. Instead, he all but shut it down when he came to power. This shows that the Big Society was always a rebranding trick – a way of making the biggest cuts to public spending since the 1920s sound upbeat. I'm not taking away your library, I'm empowering you to run it!

Deception Number Three: Multiculturalism. In a speech last weekend, Cameron argued that Britain has allowed some ethnic minorities to fall into "segregated communities behaving in ways that run completely counter to our values." We should stop encouraging immigrants to be separate and to retain the culture of the country they came from, however patriarchal and fundamentalist it might be. Instead we should promote a "liberal society" where we all mix with each other in one shared culture.

I agree. I am the son of an immigrant and passionately in favour of immigration – but the best way to welcome immigrants is not to put them in a brightly coloured box called Exotic and Different, where they are free to oppress "their" women and gays.

But while Cameron preaches against ghettoising minorities publicly, he is actively promoting it in the most important and formative place of all – our schools. When I was a kid growing up in the London suburbs, I went to school with children from every kind of family – black, white, Muslim, Jewish, atheist. Because we all knew each other as real people, few of us became racist: we'd always remember our friends and know any stereotype about them was absurd. But in the area where I grew up, that doesn't happen any more. Children are now parcelled off to separate "faith schools" – children of Christians to the left, kids of Muslims to the right, and so on.

Some 70 per cent of the "free schools" established under Cameron are religious separatist schools. They are free to indoctrinate children into deranged ideas like creationism, Hell and the caste system. So Cameron's policies ensure that many more children will be raised in "segregated communities behaving in ways that run completely counter to our values."

Yes, all politicians lie – but I can't think of many others who week after week deliver speeches demanding X, while they are ruthlessly and knowingly doing the exact opposite of X. Beneath Cameron's entire agenda runs the biggest lie of all: that Britain is facing an "unprecedented" level of debt. In reality, Britain's national debt has been higher as a proportion of GDP for 200 of the past 250 years. So here's the experiment. How many blatant lies are you prepared to take from your Prime Minister?

For updates on these issues and others, you can follow Johann on Twitter at www.twitter.com/johannhari101