Since the credit crunch, middle-class shopping habits have changed. Their preferences have remained broadly similar, it's just they no longer like to pay for things – and are now shoplifting to "keep up appearances", according to one report. The great, sprawling iniquity of the way we look at crime is right there in the headline. You never hear about a blue collar criminal doing it to "keep up appearances". You never hear about working-class crime at all, in fact, in terms of why they might be doing it – only that they do it relentlessly, being louts and scofflaws.

I have a friend who, in the middle of the last recession, used to steal by buying a Guardian on his way into the supermarket, laying it flat at the bottom of the trolley and slipping cheese into it. It was an imperfect dinner party solution, in my view, since the cheese had to be flat and relatively odourless. It basically had to be gruyère. But the principle – that the middle classes don't steal – worked. Nobody would ever look inside a Guardian for cheese, and nobody ever did.

At the level of shoplifting, I would say this fallacious assumption of middle-class honesty is no more than a curiosity. The victim is a shop, the misdemeanour is pretty minor and who really cares? These perceptions don't stop, however, at the doors of Waitrose. Research earlier this year conducted by the Fabian Society and the Joseph Rowntree Foundation asked people to estimate the social cost of benefit fraud relative to that of tax evasion – and their answers misfired by an order of magnitude that was laughable.

The majority thought benefit cheats cost more than tax evaders; in fact benefit fraud is estimated by the Department for Work and Pensions to cost £800m a year, while personal tax avoidance was thought to be running at £13bn. This misconception is more troubling than assumptions about middle-class honesty: if the taxpayer is thought to be broadly honest, while society's net recipients are all crooks, then clearly that will have an impact on our readiness to pay tax and support even the most modest redistribution.

All that is nothing, however, compared with the legal system and how it has evolved to reflect, endorse and perpetuate our most idiotic prejudices, as demonstrated by Radio 4's Thinking Allowed. This is now in the middle of a brilliant series (the final programme is next Wednesday at 4pm) on white-collar crime spurred, according to the producer, Charlie Taylor, by various factors, including the banking crisis and MPs' expenses. The reach of the programme's findings is staggering, from the sheer scale of white-collar crime to the under-resourcing of fraud squads – in favour of investigations into crimes whose significance and social cost don't even come close.

There is a tendency to think of middle-class crime (if you will admit to its existence in the first place) as victimless, since the targets tend to be corporations. But of course the proceeds don't exist in a vacuum; they exist as individuals' pensions, so white-collar crime is morally no different to a bloodless mugging in an alley.

But there is also the tendency to think of this sort of wrongdoing as lacking any violent aspect. Taylor stresses that corporate crime can and does manifest itself in workplace fatalities – in numbers far greater than those that are reported. He makes this additional point: "There's a different law when it comes to white-collar crime: it's much harder to detect, much harder to mount a prosecution, much harder to convict; and if they are convicted they have much shorter sentences in much nicer prisons. They get let out earlier, they get tagged, they only serve a third of their sentence inside. They're deemed not to be recidivists, and thought not to be dangerous.

"You can understand this, there's some argument for it. But their social position was taken into account when they were sentenced in the first place, the judge is likely to take a loss of reputation into account. To us that seems to undervalue working-class lives. Just because somebody's a steelworker, it doesn't mean that if they get caught stealing, that isn't as much of a shock to their communities as with someone who works in an office."

It starts with a little light bigotry, a world in which the well-spoken don't lie, in which a Guardian reader can steal gruyère without getting caught; and it ends with a legal system that isn't just two-tiered, but bears down with its full weight on blue-collar crime, and will prosecute a bent accountant only grudgingly, as an afterthought.

It's easy, it's often a bit funny, it's egregious, this assumption of honesty as a matter of breeding; but it is also particularly worth revisiting, re-evaluating, and then ripping up – now, while we are in the eye of so many conversations that hinge upon it.

From regulation in the City and the perks of parliamentarians to the future of benefits and tax in the coming lean years – not to mention the fact that fraud is already on the rise and is expected by City analysts to treble during this recession – all these issues will be better resolved if we recast these bankers and solicitors, these trusted professionals, as just hoodies with good jobs. Stop giving them the benefit of the doubt. Ban them from the Bluewater of your heart.