The recent spate of milkshake protests against the far right began in Warrington on 2 May. A young Asian man was being harassed by Stephen Yaxley-Lennon (a.k.a. ‘Tommy Robinson’, formerly of the BNP and EDL, now Ukip). As henchmen bristled around him, he defended himself with what came to hand. Yaxley-Lennon got another dousing in Wigan the next day, and Nigel Farage caught a banana and salted caramel coating in Newcastle earlier this week.

Various professional hyperventilators have decried the apparent coarsening of British politics and predicted a rapid skate down a slippery slope. But this form of grassroots censure has a long history. George Eliot wrote of Mr Brooke being ‘disagreeably anointed’ under a ‘hail of eggs’ while campaigning in Middlemarch; mid-20th-century Greeks used yoghurt; ancient Roman colonists upbraided Vespasian with turnips; John Prescott suffered both egging and soaking with an ice bucket while deputy prime minister; both David Cameron and Ed Miliband were egged on the campaign trail. More disturbing and worthier of concern is the support gathering behind Farage’s latest electoral vehicle.

According to one analysis, Brexit Party voters are victims of a con. The party has published no manifesto, its democratic and financial structure is murky, and its only policy – to deliver a Brexit that is ‘hard’, ‘clean’ or ‘full’ – is vacuous and protean. Such an ill-defined goal allows Farage to reject any Tory attempt at implementing a withdrawal agreement as a quisling’s compromise. Unhindered by detail, he portrays himself as a defender of democracy against the ‘establishment’. Posing as both tribune and emancipator of the 52 per cent, he intends to massage their sense of betrayal and outrage into electoral support for his longstanding nationalist agenda. For the time being, the argument goes, he carefully conceals his darker purposes behind a one-note message of Brexit betrayal. If only people knew what he really wanted, they wouldn’t vote for him.

This view is exemplified in the ad campaign run by the anti-Brexit pressure group ‘Led by Donkeys’. It initially made a splash by displaying examples of hypocrisy or deception by leading Brexit enthusiasts, and has now taken to putting up fake campaign posters for the Brexit Party – advertising Farage’s desire to privatise the NHS, for instance. Ann Widdecombe’s face appeared next to a quotation – ‘Homosexual acts are wrongful’ – and a political interpretation: ‘Target gay people.’ Context and condemnation were saved for the small print. There are some obvious problems with this strategy, not least that the billboard was in a safe Conservative seat that returned one of parliament’s most assiduous homophobes at the last general election. A sizeable chunk of passers-by may simply have nodded in assent, and gone on their way buoyed by the apparent return of old-fashioned common sense. It speaks highly of the campaigners’ morality that they couldn’t imagine anyone agreeing with such a bigoted statement, but less well of their political acuity.

They took down the Widdecombe poster when all this was pointed out to them, but their key assumptions remain: people who are likely to vote for the Brexit Party are either being deceived, or simply do not know that the party’s candidates are variously hypocrites, antediluvian reactionaries or epigones of the alt-right. There are leaps in reasoning here: some voters will agree with the candidates’ positions anyway; others will be willing to hold their noses; and most don’t find hypocrisy (especially over technical details) as animating as the liberal left imagines. But the position has its merits, too: Brexit has been so calamitous in part because it has been abstracted away from broader questions about what kind of society and what kind of state we want to live in; insisting on the connection between Farage or Widdecombe’s wider politics and their ‘no deal’ advocacy tells us what kind of Britain they would like to build, given the chance. Yet the greatest risk of this way of thinking – other than a latent tendency to think of voters as easily gulled – is to accept the implicit claim of Farage’s new party: that he and he alone speaks for everyone who voted Leave.

Farage has a long history of stalking the porous borderline between mainstream conservatism and the far right. When he took over Ukip in the late 1990s, he saw the chance to transform Alan Sked’s eccentric fringe party into a clearing house for far-right ideas while also making inroads into the europhobic Tory base. Yet he has always been careful to disclaim the outright fascists and ethno-cranks: when asked to distinguish between Ukip and the Brexit Party, he claims ‘no difference’ in policy but a great one in personnel. It also has a new structure, highly geared to media intervention, stripped of many of the cumbersome integuments of old parties – branches, internal democracy, committees, middle layers – and centred on a charismatic leader. (The same digital structure distinguishes the new far-right campaigners from their predecessors.) The ultimate prize is not the elevation of a minor schismatic right-wing party, but a conservatism rid of the insipid pieties of Cameronism and bearing Farage’s reptilian grin. A betrayal myth – according to which all parties, but especially the Conservatives, are in dereliction of their democratic responsibilities – allows him a far greater opportunity for legitimation than Ukip ever provided.

How do you defeat him? It’s dangerous to think there could be a secret trick that will bring him down, like pouring water on the Wicked Witch of the West, but allowing some ideological air into a room currently muggy with pandering might help. The billboard campaigns and the milkshake throwing both recognise that Farage represents a particular kind of politics, worth naming and fighting against, and that in all the technical, legal and procedural arguments around Brexit, the political and ideological can get lost. The Conservative Party is unlikely to inoculate itself against the influence of the headbangers before the election of its next leader; whoever that turns out to be will largely be a creature of Mr Farage. Whichever route the Labour Party eventually takes through its uneasy relation to Brexit, it will have to press the Tories on their capitulation to the far right. Until then, I’ll take a strawberry shake, please.