The modern mind recoils from nuance, detail and reflection. Bombarded with digital information, we seek instant gratification, confuse good public policy with instant customer service, and reserve special contempt for those who would delay the Deliveroo of democracy.

So it was no surprise that Arron Banks, the Leave.EU donor now under investigation by the National Crime Agency, framed his interview with the BBC’s Andrew Marr as just another pesky metropolitan attempt to confuse and obstruct the supposedly simple matter of Brexit. The harder Marr pressed him on the ultimate source of his £8m loan to the campaign, the more irritated Banks became (“I don’t want to get heated with you”). Any authority or source of information that the presenter cited – the Financial Times, the Electoral Commission, the Commons digital, culture, media and sport (DCMS) select committee – was instantly dismissed as biased or otherwise tarnished. The most telling remark of the interview was Banks’s disdain for “the number of corrupt MPs who have sat in this seat over the years”.

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As usual, he postured as the straight-talking tribune of the people, whose will was yet again being challenged by whingeing remoaner liberals. His whole countenance screamed a single complaint: why do you lot have to make things so complicated? Quite how complicated Banks’s financial affairs are, and have been, is now the subject of a criminal investigation. Its outcome ought to be awaited with fretful concern by the Westminster class, with less than five months to go until the UK’s scheduled departure from the European Union.

Which is why it has been so depressing to behold the parade of politicians of left and right insisting that the allegations against the insurance and mining tycoon should have no bearing at all upon the way in which we perceive the result of the 2016 referendum. Most ludicrous of all has been the claim of the Corbynite left that social media – the digital campaigning paid for by Banks – played no significant part in the vote for leave. Really? This seems an odd argument, given that the Labour party made extensive use of a specially created social media targeting tool called Promote in the 2017 general election, and that Jeremy Corbyn himself joined Snapchat to record his political travels. Was he wasting his time, too?

Facebook Twitter Pinterest ‘When the margin of victory is that slender, little things mean a lot.’ Photograph: Leon Neal/AFP/Getty Images

You don’t have to be a remainer – or you shouldn’t have to be – to be alarmed by the latest disclosures. For more than two years we have been told with bludgeoning certainty that the people have spoken, the verdict is in, the decision is final. But what if the process by which that decision was reached was seriously corrupted?

Thanks to the epic work of Carole Cadwalladr and other journalists, a mass of evidence has now accrued that the two main pro-Brexit campaigns were engaged in electoral vandalism, astonishing levels of disinformation and breaches of the law governing referendums. Yes, that evidence is often technical. But is complexity now excluded from the political process and the pursuit of justice? Are we meant to shrug our shoulders and wilfully confuse detail with trivia?

The great conflict at the heart of the Brexit process has been the tension between simplicity of feeling and rhetoric on the one hand, and complexity of fact and negotiation on the other. According to the Sunday Times, Theresa May is close to finalising “a secret Brexit deal”. And it is certainly true that a mood of cautious optimism has settled upon the talks. But much still depends upon political and diplomatic issues that are both extremely complicated and immensely significant. How, precisely, would the UK’s continued participation in the EU customs union affect its relationship with the European court of justice? And what sort of “exit clause” to manage our eventual departure from the EU customs union do the negotiators have in mind? Yes, these are technicalities. But so are the working parts of jet engines and the nanotechnology inside an iPhone: and nobody disputes that they’re quite important.

But – if you insist, and just for the sake of argument – set Brexit aside. When Damian Collins, the chair of the DCMS select committee, met the FBI in Washington DC to discuss its inquiry into fake news and electoral manipulation, he was struck by the extent to which the Feds’ focus had already shifted from the 2016 presidential race to future elections, including this week’s midterm contests. Its message was: defend your democracy against even more aggressive attacks upon its electoral processes. Think of the next general election, which could come at any time. Or – if you truly believe that vote will not be held until 2022 – concentrate on the elections in 270 English local authorities that will be held in May. How safe are those contests from sabotage subsidised by dark money?

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Banks is only the most spotlit of a new cohort of digital godfathers seeking to use wealth and technology to manipulate our democratic institutions. He is the John Gotti of populist campaigning, a dapper don who relishes his public profile. But there are plenty of others – state actors and private individuals – who stay out of the limelight and prefer secret power to boisterous publicity.

Are we really OK with this? And, to return to Brexit, is our impatience to get on with this total transformation in our institutional and commercial arrangements so all-consuming that we cannot even contemplate a pause for thought? Call me a remoaner. Call me a centrist. Call me an “enemy of the people”. But don’t insult my intelligence by pretending that there is not a noxious stink emanating from the 2016 referendum campaign.

And yes: I know that 17.4 million people voted leave. But 16.1 million voted remain, too. When the margin of victory is that slender, little things mean a lot. And the Banks criminal investigation is more than a little thing. Indeed, we long ago reached the critical mass of evidence where a political class of any statesmanship would have had the courage to suspend the Brexit process and establish beyond question that the original 2016 campaign was conducted fairly. This is no time for bovine paralysis or foot-shuffling timidity. If the satnav is leading you off a cliff, and you think it might have been tampered with, is it really an act of treachery to apply the brakes?

• Matthew d’Ancona is a Guardian columnist