"Avoid," it said: "vt ... to evade, escape". Then I read on a bit. "Evade": vt ... to escape or avoid by cunning". Unless there was a nuance I overlooked, this exemplary guide to the language says you avoid by evasion and evade by avoidance. Has anyone told Her Majesty's Revenue & Customs?

In law, the comic Jimmy Carr avoided but did not evade certain tax liabilities. As he sometimes says, with a grin that cries out for smack, they can't touch you for it. He avoided with enthusiasm, to the tune of £3.3 million annually, but he wasn't cunning about it. Now he's very sorry. Why is that? David Cameron, presiding over the Cabinet full of millionaires that just cut the top tax rate for millionaires, called Carr's accountancy hobby "morally wrong". Yet the scheme – to funnel earnings through a Jersey-based firm in exchange for tax-free "loans" – was cleared by HMRC. As far as Carr was concerned, no laws were broken. So why is he apologising for "a terrible error of judgement"?

Cameron could legislate against this sort of thing, of course. That's what governments do in the face of immoral behaviour. But the Prime Minister and his chancellor, George Osborne, would then have to stop telling those who can afford the lawyers and the tax accountants that a bit of honest avoidance is perfectly acceptable. Such is, after all, their fundamental position. If the scheme is not "aggressive", as Osborne puts it, you can protect your earnings to your heart's content.

Who wouldn't? For those who see tax evaporate from their payslips by the week or the month, the question is academic. Hence the uproar.

Many, if not most, would welcome the reliefs – in every sense – enjoyed by the rich and famous.

They would probably echo Carr's response to an audience member in Tunbridge Wells, that hotbed of radicalism. "I pay what I have to and not a penny more," he said. But Carr has, or had, a choice in the matter; millions have no choice.

Cameron senses the anger. It's not what the rich do, obedient to sheer self-interest, but the fact that they can do it at all. It's not the fact of greed – for few of us are naive – but the fact that so little is done to deter the greedy. Yet in any other context Cameron would be talking about enterprise, rewards, and refusing to penalise British success stories. All he seems to mourn in the behaviour of Carr and the rest is a lack of discretion.

The game is as old as government. As soon as one tax loophole is closed, another is found. Some accountants spend their waking hours attempting to spot chinks in the state's armoury, and charge handsomely for their insights. The one law that is never broken is the law of unintended consequences. Governments have a habit of using the tax system to encourage industry. The intentions, as often as not, are sound. Periodically the cry will go up, for one example, that British cinema is in dire straits and needs to be saved. What's to be done? "Tax breaks," comes the reply. The inevitable result is a stampede of tax-avoiding cineastes rushing to shelter their spare cash in straight-to-DVD art movies.

There is nothing new about it. Back in the 1980s, famously, the Thatcher government decided it wanted to aid British forestry. The result was that the likes of Terry Wogan and Cliff Richard wound up as the proud (if absent) owners of a lot of Scottish trees. Forestry expanded hugely, but the tax subsidies meant the country was beautified with some of the most expensive timber yet planted. The celebrities did well, and all was above board, but the exchequer was deprived of a fortune.

The losses have not ceased. In fact, if you believe the Tax Justice Network, the schemes of celebrities such as Carr are paltry, even trivial things. Cameron's decision to make an example of a comedian counts, in fact, as handy distraction.

Last November, the network claimed that Britain is losing £70 billion annually to tax avoidance, most of it corporate, while Osborne claws £18 billion from the welfare budget and his colleagues inveigh against unaffordable public sector pensions. Set beside the likes of Barclays Bank, Carr is the smallest of small fry.

Cameron talks of morality, not of the culture – his culture – in which moral judgement is subservient always to economic imperatives. Perhaps Jeremy Hunt, culture secretary and Murdoch fan, could enlighten his prime minister. Just before the last election Hunt was paid a dividend by the company he founded. It came in the form of half of the firm's office building. Those offices were then leased back instantly to the company. Reportedly, the deal allowed Hunt to reduce his potential tax bill by more than £100,000 because it was completed days before Osborne announced a 10% increase in the tax on dividends.

Hunt is still in the Government, but Carr is in the doghouse. There's no harm in that, not if you've watched the comic's head inflate with smugness. More important, however, is the ebb and flow of public opinion. When did we reach the point at which the behaviour of the rich and famous could be both perfectly legal and "morally wrong"?

Why are we still listening to the self-serving quibbling over the difference between evasion and avoidance?

Few will have failed to notice that the very wealthy have managed to shelter their money with no difficulty through two bouts of recession. Some of those busy minimising their taxes were instrumental in wrecking the British economy. Earlier this year Osborne announced that he was "shocked" to discover just how little tax is paid by some of these people. Then he gave them a tax cut.

He allows them to pay a token fee in return for their "non-dom" loot. He tolerates their capital gains scams, their investment write-offs, their overflowing pension pots, their fake charities, their offshore arrangements – Jersey is nice at any time of the year – their contrived business "losses" and their dividend schemes. Like all of his predecessors, he tinkers at the edges.

In essence, Osborne believes that this is how the world must be. If you enjoy a paradox, such is the price we pay for wealth creation.

Next year, the Chancellor means to introduce something he calls a "general anti-avoidance rule". It will amount to a mere presumption, for HMRC's guidance, but it will be presented as a crackdown.

It will not amount to telling the richest that income is income and that at the top end 45% is owed to the exchequer. We wouldn't – would we? – want to drive those wealth creators from our shores.

Then their accountants and lawyers will set to work, yet again, in search of relief for Britain's downtrodden oligarchs.

Carr's case is a mere diversion, but his contrition is fascinating. He broke no law and yet, embattled, knows he did something wrong. After all, who boasts of "perfectly legal" tax avoidance when millions are on the financial brink? None of them does. There's a clue in that, for honest legislators.