will bet you the price of a roll of gold wallpaper that you will be able to say who paid when you last had the decorators in. If there was any reason you had to prove that it was you, you’d produce a bank or credit card statement. The home life of Boris Johnson is much more complicated. There are now no fewer than three inquiries into how the refurbishment of the Downing Street flat was funded. “Cash for cushions” and “wallpapergate” are amusing labels for this scandal, but I have an issue with them. They sort of serve Mr Johnson by putting a trivialising wrapper on the profoundly serious questions raised. One of these inquiries is by the cabinet secretary, Simon Case, so green for the role that he hasn’t got the customary knighthood yet. Another is by the newly appointed “independent” adviser on ministerial standards, Lord Geidt. The prime minister can fire Mr Case just like he sacked the last cabinet secretary. The prime minister can ignore Lord Geidt. He did that to the previous ethics invigilator, Sir Alex Allan, who resigned when Mr Johnson refused to accept his findings about bullying by Priti Patel. I am not saying the two men won’t try to do a proper job, but any arrangement that involves an official inquiring into his own boss does not inspire 100% confidence. The investigation that Mr Johnson has more to worry about is that by the Electoral Commission. That body has independent, statutory powers to interview witnesses under caution and gather evidence. If it concludes there was wrongdoing, it will impose a fine. If it decides that there are reasonable grounds to suspect that a criminal offence has been committed, the commission can refer the case to the police. This is the probe causing the strongest ripples of fearful panic through Number 10 and Tory party HQ. It is also menacing for Mr Johnson that there is a good prospect of a fourth investigation, this one by the commissioner for parliamentary standards, who has rebuked him in the past for rule-breaking. The prime minister claims to have “covered the costs” of the refurbishment, but he has repeatedly failed to deny that a large bill was originally paid for by someone else, either through a loan or a donation, neither of which was declared. He dismisses all the questions about his behaviour as a “whole farrago of nonsense”. This is what poker players would call a tell. Those familiar with his pathology will know that he often dials up the bluster when he has something to hide. The worse the misconduct he is trying to conceal, the rantier he tends to get. He was very ranty indeed at the most recent prime minister’s questions. If this is genuinely a “farrago of nonsense”, he could clear it up today and save everyone a lot of time by showing when he paid the bill. There must be a reason he won’t do this and the reason must be an extremely compelling one given that he’d apparently prefer to endure days of rotten headlines in the run-up to this Thursday’s big set of elections rather than give us full disclosure. We know that he is a twice-divorced man with about six children (estimates vary) who constantly moans to friends that he is strapped for cash. His fiancee is reported to have expensive tastes in home decor and friends who sneer to Tatler about the “nightmare” furniture available from John Lewis, a store most voters think of as upmarket. The nature of his evasions fuels the very strong suspicion that he did not pay the original bill, but only belatedly and reluctantly coughed up to try to cover his tracks. That suspicion has been greatly hardened by leaked emails and Dominic Cummings’s accusation that Mr Johnson hatched “an unethical, foolish and possibly illegal” scheme that “almost certainly broke the rules” in having donors secretly finance the renovation. There is a shoulder-shrugging view that none of this much matters. One senior Conservative MP told me that he was sanguine about the sleaze stories swirling around Number 10 because “I have honestly not had a single email about the wallpaper”. Other Tory MPs contend: “Voters won’t care who paid to do up the flat if it didn’t cost them any money.” The mantra parroted by the cabinet is that the public isn’t bothered by a story of interest only in the “Westminster bubble”. This is the same line they take about the multiple-sourced allegations that Mr Johnson displayed ghastly callousness towards the victims of Covid by declaring that he would “let bodies pile high in their thousands” rather than have another lockdown. The cynical dismissiveness of many Tories is itself a symptom of the problem we have with integrity in public life. The reaction of voters has always been a factor in the impact of sleaze scandals, but to regard opinion polls as the only metric that matters is to throw away any claim to a moral compass. Transparency about who is supplying cash or other benefits to elected representatives is an absolutely fundamental principle. It is why there is a register of members’ interests, a register from which Mr Johnson is not exempt, although he has a history of behaving as if the rules don’t apply to him, making late registrations of his financial interests on at least nine occasions. For reasons that should be too obvious to spell out, we need to know who our lawmakers and decision-makers are beholden to and why, especially the prime minister. We also need to know whether he has sought to conceal his indebtedness to private interests from the public. If a man can’t be straight about how he paid for his sofa, what else might he lie about? The Nolan principles, the ethical guidelines for public office holders drawn up after the scandals of the 1990s, speak of seven virtues: selflessness, integrity, objectivity, accountability, openness, honesty and leadership. That is a utopian manifesto for perfection rather than a realistic picture of any politician you are likely to meet. The ideal political animal described by Nolan bears a vanishingly slight resemblance to the current tenant of Number 10. So the system has come to depend on rules. Most of these were formulated in a haphazard fashion in reaction to past outrages, such as that over parliamentary expenses, which revealed that politicians cannot be trusted to invigilate their own conduct. That has left us with a patchwork of registers and regulations, some of which are riddled with loopholes. Were it not for resourceful journalism, we would never have found out about David Cameron’s behind-the-scenes activities on behalf of Greensill because his influence-peddling was exempt from the disclosure rules on lobbying that he enacted when he was at Number 10. The policing of the behaviour of ministers is particularly weak and creaking under the intense stress test of trying to keep a Johnson government honest and ethical. Adherence to the ministerial code still greatly depends on the discredited theory that politicians are “honourable fellows” who can be expected to behave properly. When they don’t, we are supposed to have the additional reassurance that civil servants will act as moral gatekeepers by “speaking truth to power” and intervening to stop ministers behaving badly. I am sure there are officials who still try to perform that vital safeguarding role, but their enthusiasm for doing so has been deliberately cooled by the regime at Number 10. A lot of senior mandarins have been purged from Whitehall since Mr Johnson became prime minister. Officials would not be human if they did not have that at the back of their minds when debating whether they feel brave enough to confront misconduct by a minister, especially if it is the one who lives at Number 10. The prime minster is the sole arbiter of whether alleged offences against the code are worthy of investigation and the ultimate decider whether there should be any punishment for transgression. This is a ridiculous nest of conflicts of interest. It becomes an absolutely ludicrous one when the prime minister himself is the subject of investigation. Even if Lord Geidt or Mr Case conclude that their boss has broken the rules and even if they are willing to say so, there is nothing but shame to prevent him from tossing aside their verdicts and declaring himself not guilty. And we know shame is a sensation that this prime minister is impervious to. This is why it is so essential that properly independent investigators are on the case. That’s a court in which Boris Johnson can’t be his own judge and jury.