The great struggle on the doorstep faced by Ukip voters is not about the ins and outs of VAT, or government borrowing, or even immigration. It's about whether they're racist or not.
The old lady who answers the door somewhere in Hertfordshire and sees not one but three Ukip rosettes on her door wrinkles her face. "Doubtful," she says quietly, when asked whether she might lend them her support. She mutters something to herself which includes the word "racist".
It's a tricky situation for this group of Kippers - especially as this is the neck of the woods where they're placing their highest hopes. In Hertfordshire, the local party chairman faces the daunting challenge of taking on a Conservative vote-share of 55%. That was in 2009, when the Tories were riding high. A lot has changed since then. Ukip are riding high in the national polls. But the "racist" accusation has, evidently, not gone away.
"We're not!", one of the canvassers, Arthur, says. He left the Conservatives in 2011 a week before the EU referendum vote saw David Cameron defeated, and makes a habit of waving his membership card at bewildered voters. Arthur seems personally affronted when he is accused of being racist. He points out his nephew and niece, who are "half-Greek", would be especially upset. "We're all immigrants," he adds, underlining his point.
David, the candidate, is less confrontational. He explains he has developed a "thick skin" but admits that, initially, these sort of jibes "hurt" quite a bit. "It's a numbers game," it's "economics 101", he argues. "If you've got a pint glass, you can't put two pints of beer in it."
The old lady isn't buying it. She says something about the NHS not being able to run without the labour provided from abroad. And she's right. I can't help but remember the cheerful eastern European who cleaned up my wife after she gave birth in Stevenage at 4am. The Ukip trio trying to win her over are playing more of a zero sum game. "There are too many human beings, full stop," they explain, let alone immigrants.
At the end of their conversation no progress has been made. The old lady is just as full of doubts as ever. So David, Arthur and Tony move on. We're knocking on doors on a row of fairly well-to-do houses on the main road out of Hoddesdon. It might be Hertfordshire, but this feels an awful lot like Essex. And, if the voters we're talking to are a representative sample, Ukip are about to romp home with about 99% of the vote.
They are not representative, of course. Anyone under the age of 40 or so is almost instantly a write-off. But the retirees are all more or less happy with Ukip's policies - and around these parts they are mostly retirees. This is getting ridiculous. David insists this isn't a set-up. "We're bringing people back to politics," they jubilantly declare to undecided voters. The local Tories are written off as "complacent". "I assure you we'll start shouting," David tells one voter solemnly.
Convincing voters they're not racist is one thing, but dealing with the challenge of thoroughly passionate supporters of their views is quite another. "Every job there is is going to a bloody foreigner," complains a man in his early 50s, interrupting some home improvements to sound off. This voter is clearly a potential Ukip supporter, but he says he doesn't usually bother voting. "We're going to do something about it," David declares. "If you get Ukip in county hall, we can make a fuss about it." He's unemployed and just wants a job. Arthur gets him worked up by complaining there are students with A-levels being forced to work in cafes. It's "ridiculous".
And then the missus arrives home. She is sceptical about Ukip. "You're a bit too extreme for me," she declares. They appear dumbfounded, as if she has said something they have never heard before. "You know what I mean," she says. Arthur can't help but be personally offended. "When did I become a racist?" he demands to know. "Was it before or after I joined the Conservatives?" Out comes his Tory membership card again. The wife looks nonplussed.
But then she starts talking, and quickly admits she believes the immigration problem is a big one. "The common opinion is enough is enough." Astonishingly, David begins attempting to actually rein her in. "Most of the eastern Europeans are hard-working," he insists. They have "good manners". But she disagrees, saying she finds the eastern European children at her school to be very unpleasant. "They leer, they make pissing noises."
The missus, initially writing Ukip off as being extreme, is actually now finding her own views are much closer to theirs than she had thought. This is the biggest test for this group, I think to myself. The temptation to pander to her views must be very, very strong. In the end, it proves irresistible, and David refers to warnings from the Metropolitan police that the arrival of immigrants from eastern Europe is inevitably accompanied by a spike in lawlessness. "There's a big element of crime that comes from it," he says. "The biggest worry is the first ones, because they'll take the opportunity." Then there are the "gypsy gangs that work the streets". It's a moment of reckoning for Ukip, a blatant grab for a vote by trying to inflame and provoke people's fears.
"Racist thugs in Hoddesdon," David jokes as he imagines the terrible coverage he'll get from my article. That is laughable, for David, Arthur and Tony are not racist. Far from it. But it says something about where their support springs from that the biggest danger they face on the doorstep is from voters who share their views.