Dominic Cummings is just a troll. He may have trolled the whole country and changed the course of British history, but he’s still the man with an egg for a face, who screams everyone must be accountable for their actions – everyone except him.

MPs who want to question Cummings about the finances of his Vote Leave campaign are “grandstanding” fools spreading “fake news”. (A rich charge from an operator who told the populace that Brexit would deliver £350m-a-week to the NHS and the EU was about to admit Turkey and flood Britain with millions of jihad-inclined Muslims.) He seems as confident now as he was then. “It’s too late,” he says in effect. “We won and there’s nothing you little people can do about it.” Perhaps he’s right. In an age of Russian infowars and data harvesting, our defences against the manipulation of elections are as obsolete as black-and-white television.

For all that, I can see why he may be feeling a niggle of fear. He has become the first person to refuse to co-operate with the Commons digital, culture, media and sport committee’s investigation into the referendum and it is easy to guess why. Vote Leave spent millions buying targeted online advertising from the AggregateIQ data company. It also gave £625,000 to a student, Darren Grimes, who ran a second Brexit campaign – BeLeave. Cummings insisted Grimes was not his stooge. But evidence to the committee from Facebook showed BeLeave used AggregateIQ datasets which covered the “exact same audiences”. MPs want to know whether there was collusion between the two supposedly separate organisations and a scam to break the referendum campaign’s spending limits. Cummings says he cannot answer the charge because he is also being investigated by the Electoral Commission. Yet Alexander Nix of Donald Trump’s Cambridge Analytica has given evidence, even though he is facing multiple inquiries. As Damian Collins, the committee’s chairman said, Cummings’s excuse “simply does not hold up”.

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Cummings is the latest in a long line of Leavers who have shown nothing but contempt for the British institutions they claim to be protecting. After the Mail denounced judges as the “enemies of the people” and Jacob Rees-Mogg talked of “burning down” the Lords, we have the director of Vote Leave refusing to acknowledge the sovereignty of the Commons. The right does not want Britain to “take back control”. It wants to control Britain, and anyone who gets in its way is a fake, a grandstander, an enemy or saboteur.

A fair proportion of its bottomless supply of venom has been directed at my colleague Carole Cadwalladr. Her exposé of the Leave campaign is not a model example of dogged journalism but a “conspiracy theory” that offers Remain voters the illusion they did not really lose. Leavers never explain how they know the alleged breaches of electoral law did not swing a tight contest. Nor do they show any concern for the health of British democracy or the rule of law.

Facebook Twitter Pinterest Michael Gove at a Vote Leave rally in June 2016. Photograph: Carl Court/Getty Images

Vote Leave was the official pro-Brexit campaign. Cummings, Boris Johnson, Michael Gove et al claimed to be the serious Brexiters – a cut above Nigel Farage, Aaron Banks and the other race-baiters. As it has turned out, Vote Leave won by exploiting immigration as cynically as Farage and Banks did. They no more had a coherent plan for Britain’s future than Farage and Banks had. And now there is a prima facie argument – to put it mildly – that they were just as disreputable.

Vote Leave won by exploiting immigration as cynically as Farage and Banks did

What makes the right’s dismissal of the case against the Leave campaign so suspect is that modern elections are about access to and the exploitation of data. Cummings said that Vote Leave “put almost all our money into digital”. Yet the authorities know nothing about the sources of the data. AggregateIQ is based on Vancouver Island off Canada’s west coast. Facebook told the Commons that as far as it can work out “$2m (£1.5m) of AggregateIQ’s entire $3.5m Facebook advertising spend over the last four years appeared to be associated with the EU referendum”. The Commons discovered that, as well as supporting Vote Leave, it was also gearing up to provide support for Michael Gove’s attempt to seize the prime ministership in 2016.

Staffed by civil servants rather than the police and intelligence officers needed to protect free elections in the 2010s, the Electoral Commission has been hopeless. So uninterested was it in doing its duty, the pro-Remain Good Law Project sought a judicial review of its failure to investigate the payments to Grimes. It’s as if the Mueller inquiry into Trump’s Russia connections were being run by back-covering bureaucrats rather than investigators with the power to issue search warrants and offer plea-bargaining deals.

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The hard work has been done by journalists and whistleblowers, who have been treated shockingly. I do not know how Theresa May’s political secretary, Stephen Parkinson, has been allowed to get away with responding to the Vote Leave whistleblower Shahmir Sanni’s revelations about money-channelling by outing him as gay. Sanni is from a traditional Muslim family and the spite behind the attack devastated him. But alongside the viciousness are signs of panic. Leavers are smearing their former friends and Cummings is refusing to give evidence to parliament, because they fear the accusations against them are deadly.

In February, the pro-Remain group Best for Britain conducted private polling on what would persuade the public to accept a second referendum. A fall in living standards (and they’ve already fallen) made no difference: a majority would still say we’d had one referendum and that was enough. The NHS suffering (and it is suffering) produced a tie. But when the pollsters asked: “What if there was confirmation of cheating during the referendum campaign?”, 49% wanted a second vote and only 30% opposed. If the trolled public should realise it’s been cheated, the future will be up for grabs.

• Nick Cohen is an Observer columnist