Rajinder Singh is flicking through the Pakistani channels on his Sky box from his sofa in Wellingborough, Northamptonshire. Dressed in a crimson turban, he sits a metre from the ­enormous screen, translating the odd phrase for my benefit. He's trying to show me why he's determined to join the British National Party – the only party he considers "brave" enough to "break out of the burkha called ­political correctness".

Last year, the Equality and ­Human Rights Commission forced the BNP to change its constitution on the grounds that restricting membership to ­"indigenous Caucasians" broke the Race Relations Act. A new constitution is expected to be agreed at a party meeting this Sunday, and if it's amended both Singh and the BNP think he would be ideal as the party's first non-white ­recruit. Communications and campaigns ­officer Martin Wingfield has personally endorsed him on his blog, calling for the party to "adapt and survive and give the brave and loyal Rajinder Singh the honour of becoming the first ethnic minority member".

Singh is a 78-year-old Sikh, a retired primary school teacher and a father of two, who left India for the UK in 1967. He says he's been loyal to the BNP since he first heard BNP leader Nick Griffin on television in late 2001. "He used the word 'Islam'. And I thought, 'He's brave, he has conviction,'" Singh says. "I thought, 'It's amazing what you've said: I've always been thinking that, since my childhood.'" He wrote Griffin letters of support and eventually provided him with a character reference at his 2005 trial for inciting racial hatred. Singh has voted for the BNP in every local and general election since discovering them. "I couldn't keep away."

It feels strange to hear these words from a man in a turban, but Singh ­admits he's only wearing it for my ­benefit. He's not a religious man and is clean shaven, but he wore a turban the first time he ever had "media exposure" – on BNPTV, the party's online ­channel – and has decided to do so whenever speaking to the media because "the message carries more weight" coming from a turban-wearing Sikh.

His "message" is simple and ­depressingly familiar: he fears that Britain is becoming an Islamic republic, and Islam is dangerous. "Most of them behave very nicely, but suddenly when they get together in the mosque and ­listen to the preaching, they acquire a collective identity that is formidable. It's the collective being that frightens me."

Islamophobia is not uncommon among Hindu and Sikh immigrants, but Singh's personal history makes his all the more acute. Born in West Punjab in 1931, he witnessed the violence of Indian partition firsthand. Millions of Sikhs, Hindus and Muslims were killed during partition, his father among them, murdered when Singh was only 15. He lays the blame squarely with Muslims. Why doesn't he blame the British, the architects of partition? ­"Britain had a role to play," he concedes, "but the violence sprang from the Koran. The Muslim answer to reasoned argument is knife, dagger and bomb."

This thinking gives Singh an affinity with even the most diehard BNP ­members. He's been to several party meetings and says he never feels awkward in their company. "They treat me normally," he insists. "I feel at home." I ask if he thinks many BNP members can tell the difference between Sikhs, Hindus and Muslims. "They might think of me as a Paki," he replies. "I've had people shout 'Paki Go Home!' when I walk down the street. But that speaks much about the 'Paki' reputation – it's a negative reaction to Pakistan."

When it comes to BNP policy, Singh knows what he'll be endorsing with his membership. He thinks voluntary ­repatriation in exchange for cash would be "something excellent, something supreme" because only those who are truly loyal to the UK would choose to stay here rather than take the money. When I ask about BNP plans to give "native Britons" preference in the job market, he says this has always been unofficially the case, and spelling it out in law won't make any real difference to the lives of people such as him.

Aren't the BNP racist, I ask? "Pre-amendment, yes," he replies. "They are trying to soften up. Shouldn't the nation welcome that? It's a positive move if they get people like me, and if I'm sitting in a BNP meeting they won't say 'Throw all of them out' because they'll realise one of 'them' is among 'us'." But the BNP were forced to extend their membership beyond "indigenous Caucasians", they didn't choose to. Surely they still feel the same about non-whites? "Initially the child is forced to go to school, then it becomes his habit, and then he voluntarily goes when he sees the point of it," says Singh.

Fellow Sikhs have shunned him, but Singh thinks they are misguided. "Every Hindu and Sikh comes from a country that was a victim of Islamic aggression," he says. "Every Hindu and Sikh should be praising the BNP and thanking God that something has appeared that may guarantee that this country is not overwhelmed."

The BNP are hungry for a more ­acceptable face, and they recognise Singh may be the perfect person to provide it: he's an articulate man with a readily exploitable, deep-seated bitterness. It's clear to me that they've used him whenever they've needed to appear legitimate – at Griffin's trial, and now that they face legal action if they fail to change their constitution. "I may be being exploited," Singh says, "but there's a good underlying cause. They will be diluted." Then he smiles. "All parties use people. If they don't, they will fail."



Will the BNP let non-whites join?

If it helps them exploit hatred, yes



So this is where it gets interesting. Will Rajinder Singh, with his strategically worn turban and his visceral hatred of Muslims, become the all-new face of the BNP? The Sikh has been used for PR purposes, but will the core membership welcome him? He is change, but is he the change they want?

We'll know a bit more on Sunday when the BNP membership votes on whether it will acquiesce to the demands of the Equality Commission and accept applications from those of all races and ethnic backgrounds. Logic says they will. But when was the far right and its ragbag ever logical?

If it all goes well for Singh, he won't be the first oddball to sit uneasily within the ranks of Nick Griffin's followers. Pat Richardson, a senior BNP councillor in Epping, Essex, is Jewish and it doesn't bother her that co-adherents do a nice line in anti-Semitism and Holocaust denial. "I distinguish between my Jewishness, which is a religion, and my support for the BNP, which is purely political," she has explained. In Barking, we see Laurence Rustem, who is half Turkish. He's OK, because in the words of one of the party's former election candidates, he is only "half a wog". And it's the half that isn't that counts.

The weekend vote could change much for Singh, but it will also be crucial for Griffin, who sees genuine opportunity if he can only persuade the members to re-brand their party, however superficially, as rightwing but not obviously racist. It's the old dilemma; ideological purity v electability.

It is his hunch that there are enough people disgruntled with other groups of people to make a recast BNP quite popular, and there might be something in that. Go on to the streets and listen to the white English complaining about the Poles, the Poles being rude about the Russians, black Britons carping about Asians, Hindus being disrespectful of Bangladeshis, Singh and his ilk getting stuck into the Muslims. We live on the thin line between love and hate and given the chance, Griffin – still the extremist but ever the pragmatist – would site his party there and exploit those differences rather than defy the law and face oblivion. But that wasn't what much of the membership signed up to. Tricky.

Hugh Muir