Nick Griffin: MEP elect, BNP mouthpiece, convicted Holocaust-denier and would-be deporter of black people invites me into the back seat of his car. He jokes that there is no egg on his jacket as I move it and climb in: last Tuesday he was pelted with eggs as he tried to give a victory press conference after Sunday's election results.

On Thursday morning, a sunny day in Shrewsbury, Griffin makes small talk as we drive in his Mondeo estate to a garden centre: "Normally we'd do this in a pub but it's too early for that." From the moment we meet, there is an unspoken compact: he has never met me before but does not flinch or blanch when he does. I refuse to be shocked or angered, regardless of how sweeping or wild his claims about race.

At Dobbie's Garden Centre, less than five minutes' drive out of Shrewsbury, the BNP leader and I share a table. I sip black coffee, he swigs from a bottle of James White's apple juice. We talk about the BNP's election to two seats – North-West England for him and Yorkshire and Humberside for Andrew Brons – in the European Parliament; about being pelted with eggs; racism; whether his party deserves to be ignored because its views are abhorrent, or whether non-supporters should be told what he stands for and make up their own minds.

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Is he a racist? The denial is out of his mouth before I finish the question. Does he have a problem personally with me because I am black? "None at all." So why does he want to give me £50,000 to leave Britain? "This country is the most overcrowded in Europe."

He argues that by paying non-whites to go away he is actually working to preserve racial diversity. So, why are people throwing eggs at him? He laughs, nervously. "Obviously it's the immigration, race perception thereof, at one level, and also quite simply the people throwing eggs, the Union of Anti-Fascists, is based on the Communist Party, a little group of hardline Stalinists who've never really changed their views. So there's an ideological opposition, and racism is merely an excuse, or alleged racism is merely an excuse."

This is a recurrent theme. He is beset by enemies on all sides, including the hard left, smug liberal elitists and and nutty neo-Nazis. The last, he claims, have not forgiven him for distancing himself from his public statements of a decade ago, the Holocaust denial that saw him convicted in 1998. "The BNP has changed enormously, and in the course of changing enormously I've made myself literally the most unpopular person with Britain's neo-Nazis in the entire world."

Griffin grew up in Barnet, north London, where his mother walked him to school together with a West Indian neighbour and her children. At the age of eight he moved to Southwold, Suffolk. His father, Edgar, was a Conservative councillor who provided right-wing books for his son to read and took his family to National Front meetings. In 1975, the younger Griffin joined and became close to the party's national organiser, Martin Webster. He went to Cambridge, where he gained a boxing blue. He lost an eye in 1990 when a shotgun cartridge exploded in a fire in France.

In 1995 he joined the BNP. He took over as leader in 1999, ousting its founder, John Tyndall, in a coup. A year earlier he was convicted of incitement to racial hatred after publishing material that denied the Holocaust. In 2005, he was tried, then retried and acquitted a year later, for alleged incitement to racial hatred. Recently, he has started an autobiography – "names have been changed to protect the guilty" he laughs.

He has spent the past 10 years changing the party's image from a pack of violent thugs to something electable, softening its stance on repatriation and inter-racial marriage in an effort to make the BNP less nasty – not anti-black, but pro-English.

So, how would he feel if I moved in next door? He laughs, nervously again, and points out there is no house next door to his detached stone farmhouse home 10 miles from Welshpool. "In simple terms, if you moved in next door it wouldn't bother me in the slightest. One family doesn't make any difference at all but, erm, where does it stop?"

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So if I moved next door and my brother the other side, then that would trouble you? "Well, then that would concern me because, historically, in the 1970s I spent a lot of time in the old East End with the old community, and it was a wonderful place: poor, rough and ready, but extraordinarily hospitable and really good people with an identity of their own.

"Some of them are still there, and there's an enormous amount of really bitter hostility towards mass immigration in the old, white East End. They don't even vote for us; they're so alienated by the process they simply don't bother. If that was done to any other ethnic group, at the very least the liberal elite would be saying this is a terrible shame. In fact they'd want to stop it."

Sitting in his suit and tie, with neatly combed hair and trotting out psephological jargon, he comes across as a sort of racist version of Tony Blair: coolly spouting dodgy dossiers of misinformation to justify a "war" against weapons of mass immigration and miscegenation. Most people don't believe him; we're not sure whether he sincerely believes himself, but he's going to keep pushing his line for as long as he can.

At the moment he is trying to soft-sell repatriation. "We're not talking about turfing everybody out. We're talking about encouraging some to go. It would benefit them if we did a proper, sensible deal with countries that have suffered hugely from brain-drain, with people coming here – it's the final form of colonialism. Instead of stealing, erm, gold and old statues, we steal the people and best brains, and the countries suffer as a result.

"We would help to stabilise all sorts of countries if some of their nationals or people who originate from there returned to their homelands with some of the skills that they've learnt here and applied them to make those a better place instead of coming here because it's convenient for Britain and easier than training our own people." Xenophobia as humanitarianism is just one of his verbal gymnastics.

Why does he want me out of Britain so badly? "Large-scale multi-cultural, multi-racial societies are clearly seen to be fundamentally unstable. They only work when there's some repressive force to keep them in place. When the force is removed you get something like the former Yugoslavia or Rwanda. All the real horrors of human society are based on two tribes going to war.

"I would say in 30 years it's inevitable that Europe will face a decision which is absolutely unavoidable between whether Europe will continue on the lines it is, which is founded on Christianity ... a choice between that and becoming an Islamic caliphate. There's no question about it, the government figures show it."

What would he do, then, if one of his three daughters brought home someone like me? "I would be as disappointed, as I know many Sikhs, Hindus and black people would be, and I'd talk to them both about it, try and put them off. But in the end that's their business.

"Children grow up and do their own thing. I wouldn't go as far as, say, someone from the orthodox Jewish community could well do, which is to hold a funeral, a symbolic funeral for them. But I would ask you again – unless you're going to condemn the Chief Rabbi, Jonathan Sacks, for writing a book called Will We Have Jewish Grandchildren? – don't call me a racist, or some kind of wicked bigot, for saying I would be very disappointed."

Here lies a clue to his single-handed conversion of the BNP into electability over the past 10 years: while what he says is frequently outrageous, deeply racist and often factually dubious, the way he says it – pointing to other ethnic groups allegedly acting in the same way – is designed to appear as devoid of malice, and simply an appeal for an equal hearing.

Colour, he claims, is being replaced by culture. Muslims, he says, are a community with whom everyone has a problem. I point out I don't have a particular problem with Muslims. But he does, and he expounds at length about it. He believes there is a fault line in British society. "The fault line isn't colour: Enoch Powell got that wrong. The fault line is between Islam and the rest. Islam will conquer Europe. It won't do it through guns: it will just do it through having lots of children." He blithely claims Muslims routinely groom young, non-Muslim girls for sex, that the Koran is a manual for the overthrow of the West.

I cannot let this pass: surely he doesn't believe any of that. It's nonsense isn't it? "Nope. There's an utter gulf of comprehension between us, isn't there?"

I point out that the vast majority of people in this country are either highly antipathetic towards him or just apathetic. A minority may support him, but they are out of touch with reality. Most sensible people ignore the BNP or think they're a bunch of crazy folk.

"Your perception of a vast number thinking we're a bunch of dangerous crazies is coloured by the fact that your work colleagues, the social circles you mix in and so on [are liberal] – a self-reinforcing groupthink thing."

I suggest that he can't stop multiculturalism, and he spirals off into fantasy. "If we'd been sat in café anywhere from East Berlin to the Urals in 1988, anyone who was of the mindset of Pravda, Izvestia and so on would have said you can't stop Communism. Inevitability is the chief weapon of totalitarianism, and we do live in a totalitarian society."

Can he see why some people might think he was like King Canute trying to hold back the tide of multi-culturalism? "You may well be right. I could have a more comfortable life if I went along with the flow and said 'yes, it's inevitable'. Do you think I should just pass by on the other side of the road and let it happen? Why should I do that?

"So yeah, we may not win. I don't believe we have a God-given right to win or come to power. It's not even likely. But the more successful we become, the more opponents will have to co-opt our policies."

Why such outbursts? Did black children steal his lunch at school or beat him? "I don't hate or have any problem with black people other than I hope very much that they remain black people. Other than I hope their children will look as black as they are, and as different and as interesting. And where it doesn't happen: it's not my business. No, I haven't got a problem, so where does it come from? I don't really know."

Your Views, Please: The liberal's dilemma

Should we ignore the BNP, denying it the oxygen of publicity, or engage, thereby giving it a platform? The IoS – on balance – takes the view that it should be subjected to intense scrutiny. We would appreciate your views below or e-mail us at: sundayletters@independent.co.uk