THE apathy of the status quo is a robust thing and becomes tyranny when coupled with the twin desires to preserve tradition and defer to the rich.

How else do we explain the cleaving to unequal systems that see the poorest hammered for tax while the wealthiest find ways to snake their cash away from the Inland Revenue?

An artefact of colonial Britain, non-domiciled status was introduced by William Pitt the Younger in 1799, when the country was doing battle with Napoleon, to shelter citizens with foreign property from new wartime tax regimes.

The historic loophole has squatted in the tax system ever since, periodically seeing off challenges to its survival.

What might Pitt the Younger think of his tax regime, designed for citizens in overseas colonies, being used by jet-setting celebrities and business executives?

George Osborne tilted at the scheme in his 2007 conference speech but by the time he became Chancellor of the Exchequer his sights had shifted from addressing an iniquity that supported the very rich to punishing struggling families with the two-child benefits cap.

Labour, in 2008, introduced a charge on those registered as non-domiciled, which rises depending on how many years the tax payer has lived in the UK. There were concerns the £30,000 fee would send non-doms fleeing to, say, Switzerland, but reports of their exodus were greatly exaggerated.

Every so often, the system comes to public attention when someone well-kent is found to be using it. In 2015 there was outrage when HSBC’s British-born and raised chief executive was exposed as a non-dom, able to register as such for tax purposes because he had worked in Hong Kong.

This was despite having lived in England for the 12 years prior and sending his children to school there.

That same year Ed Miliband promised to end the colonial-era inequity if he won the election but it wasn't enough to persuade voters.

Now it's the turn of Akshata Murty, a multi-millionaire who is richer than the Queen. The 42-year-old's wealth comes from a 0.91% stake in her billionaire parents' company Infosys and she owns a property portfolio of homes in the UK and California.

Ms Murty is, it has emerged, registered non-dom and is, of course, also the wife of the chap who sets the tax policy for the UK. How awkward.

Non-doms pay UK income tax and capital gains tax on any UK income and gains but not on income generated overseas, unless they choose to remit it to the UK. Those mugs domiciled here pay tax on all income and gains, no matter which country the revenue comes from.

In response to questions about her tax status, a statement from Ms Murty defended her non-dom status by implying that her hands are tied because India, her country of birth, does not allow its citizens to hold two passports.

This is a fudge, a disingenuous fudge at best, and offensive to voters' intelligence at worse. No one is compelled to be non-domiciled by circumstance: the tax payer must register themself as a non-dom and pay the aforementioned fee for doing so.

The intent here is to pay as little tax as it's legally - and this is all, it should be emphasised, legal - possible to do so. Which is quite a look for the woman whose husband, Rishi Sunak, holds the national purse strings.

There have been complaints that it is sexist to lump a woman's financial business in with her husband's job, as though she were a mere extension of her mister.

In this instance, however, we're talking about a husband who is tasked with setting tax policy, which creates a staggering conflict of interest when the wife is achingly wealthy and the husband is weighing up the pros and cons of who to tax and how.

In order to secure non-dom status, the tax payer has to prove that their natural home is not the UK and that they are here temporarily and may return to their natural home overseas.

How the very wealthy organise their financial affairs is a great mystery to a great many of us who merely accept what is automatically removed from our pay slips and whose biggest worry is the best rate of interest on an ISA. Stocks and shares ISA? Fixed rate? That reminds me, I really need to open a LISA while I'm still young enough.

We turn to Martin Lewis for financial guidance and leave the tricksy stuff to those at the top of the financial food chain.

So it's impossible to know how Ms Murty has persuaded the tax office that her natural home is elsewhere, despite all the evidence to the contrary. There's no point speculating.

Countering the smoke and mirrors of the financial dealings of the very rich, there is a plain and simple edict: a test of basic fairness.

It is no surprise that a multi-millionaire might take steps to minimise the amount of tax she pays. The surprise would be a member of the super rich who doesn't do so.

The problem is the continued existence of such an arcane law - one unique to the UK - and the reasons it survives.

It persists due to the reluctance to disturb or challenge the very rich, partly because these are Conservative party donors and friends, and partly an unwillingness born of the belief that what is good for those at the top is good for the country entire.

This couldn't be further from the case. Tax is supposed to be the great leveller - there is nothing more certain than it, after all. But, of course, that is not the case.

We all use roads and police and the NHS and the majority of the other services paid for by our contributions, but some may escape their fair contributions and others may not.

Rishi Sunak's popularity has plummeted rapidly from his cringe-worthy but at least positive Dishy Rishi to a perception of him as out-of-touch with the public mood – donating large sums to a private school while state schools struggle; failing to see the optics of non-dom status while Britons struggle in a cost of living crisis.

This week National Insurance changes introduced by the Chancellor will cause those on lower incomes to see more money deducted from their pay packets while it emerges his wife is doing what she can to avoid paying tax.

Tax is a question of morality. We pay tax to be active, contributing members of society. It is a basic, collective good. If the Chancellor of the Exchequer's wife lacks the probity to commit to that principal then she robs him of credibility.

It will infuriate voters, rightly, but they are too used, now, to these types of tales, unshockable and resigned. That fact, there, is the real scandal.