The BNP is well known for having controversial policies, but it would appear the party also has controversial opinions when it comes to canvassing voters.
An undercover reporter from the People tabloid recorded what happened when senior party member Richard Edmonds was out leafleting in Dagenham.
When a woman told him she would not vote BNP, Mr Edmonds' response as he walked away was: "Silly ******* aren't they? Maybe she's got a black kid you see? Or maybe her sister's got a black kid? That I think is always the explanation around here. Once they go with blacks, they're part of the black tribe. Wicked, horrible, stupid. I've seen it many, many times."
Mr Griffin was also filmed talking about canvassing in Barking, where he is trying to oust Labour's Margaret Hodge.
"Yes, it's something like leafleting central Nairobi isn't it, I'm afraid," he said.
A spokesman for the BNP said the remarks were made after Mr Edmonds had been verbally abused in the street. The party did not want to comment further on the filming.
At its manifesto launch last week, the BNP insisted it was not a single-issue party.
Nick Griffin: Barking's just like central Nairobi
Inside hate-filled world of BNP as boss bids to be MP
Race-hate peddler Nick Griffin launched his bid to become an east London MP by likening the seat to Nairobi - one of Africa's biggest cities. The BNP leader made the sneering comparison to Kenya's capital as he prepared to go out canvassing in Barking, where about a fifth of the population are from ethnic minorities.
He smirked: "It's something like leafleting central Nairobi, I'm afraid."
The jibe reveals racism is still at the core of the British National Party - and makes a mockery of Griffin's insistence they are not hawkers of hate.
He made the remark to an undercover People reporter who joined the BNP last month - and landed a job as Griffin's minder. Within days our man was signed up as a minder and was asked to the home of BNP stalwart Richard Barnbrook, a Greater London Assembly member.
When he arrived at the house in Dagenham, he found Griffin tying his shoelaces ready to start canvassing in nearby Barking. It was then that Griffin - bidding to oust tourism minister Margaret Hodge as MP and overturn her 12,183 majority - made his sick crack about Nairobi.
Our man told Griffin he had been harangued while canvassing for the BNP with party activists in Dagenham the day before. Griffin replied: "Well, when you think about what they have been told it's not surprising. They think you are on their doorstep to eat their baby."
Our man also told Griffin he had seen BNP supporters clash with members of United Against Fascism at the UK Border Agency office in Croydon two weeks ago. Griffin blamed police for the violence, whining: "They want to spark a reaction - that's what goes on television. The police are a bit caught because if they stop them too early they'll get done for abusing their human rights to protest. They've let it basically go too far. That's a lot of the cop-out."
Griffin said he picked Barking for his election bid because his anti-immigration stance appeals to white working-class voters who feel abandoned by Labour. As he took to the streets with camera crews in tow, Cambridgeeducated Griffin said: "There's a lot of support for us round here from honest, hard-working people who are fed up with being lied to."
Our man watched BNP activists knock on at least 1,000 doors - but only five potential supporters shook his hand. Later, Griffin told a radio phone-in he discussed immigration with a West Indian family he met canvassing - and claimed they backed his views.
He said: "They were saying the same as white people - that our kids are at the back of the queue when it comes to housing behind Somalis and Albanians who have only just arrived and it's not fair. There are plenty of West Indians agreeing with our message that Britain's full. They're not racist and nor are we."
But at no time during the hours we spent with Griffin in Barking did he talk about immigration to any West Indian family.
Griffin last night stood by his Nairobi jibe. He said: "Labour has given housing to West Indian immigrants because they need the black African vote after years of neglecting the white working class."
Catalogue of shame
Our man was routinely exposed to the violent hatred infesting the BNP during his three-week probe.
Desmond O'Flynn - who says he is a BNP organiser and boasts of having a criminal record - ranted: "I hate Muslims. I'd love to be a candidate in the election but I've got too much previous."
Gabriel Angelos, standing as a councillor in Enfield, also bragged about his violent past and raged against anti-BNP campaigners. He said in front of his own young daughter: "I hold them in contempt, the f***ing bastards."
And Richard Edmonds, 57, told our man not to visit addresses in Barking marked with an "F" on his copy of the electoral roll. He said: "F is for foreigners. There's no point talking to them. They're doing very well out of us and they want all their tribe over here."