Nine years ago BNP leader Nick Griffin set out plans to cleanse the party's image in his bid to win over the media. On Thursday he joins BBC's Question Time, an appearance that has already caused controversy – will his views be rebuffed, or will he flourish in the media spotlight?

The following correction was printed in the Observer's For the records column, Sunday 1 November 2009

Below we reported that Nick Griffin joined the BNP "after it won a council seat in Millwall in south London", but Millwall is a ward of the London Borough of Tower Hamlets in east London; confusion arose because Millwall, the football club has its home in south east London.

Two impressions strike visitors stepping off the commuter train at Dagenham Docks. The first is unmissable: the vast walls of the Dagenham Ford plant dwarf the station. The second takes longer to sink in: how quiet the factory is.

Dagenham was once as much a Ford Motors company town as Dearborn, Michigan. In 1953, Ford employed 40,000 workers. Car production stopped in 2002 and the plant is now merely a supply centre, employing just 4,000 and providing engines for cars built elsewhere. The BNP has moved into the space left by the collapse of manufacturing and the trade union politics that went with it.

Not that it is a racist hellhole by any means. On the streets you have to work hard to find people who are proud to admit to supporting the BNP. A man pushing a baby in a buggy, who would only identify himself as "Nemo", hated being treated as an ethnic minority. "Every form I get has a box I have to tick saying I'm 'white British'. I'm not British, I'm English, and the BNP is the only party that stands up for people like me."

I won't pretend that he's typical. After the BNP became the second largest party on the council, Labour activists reported that black mothers were in tears, worrying about what would happen to their children, and thugs attacked a disabled man with baseball bats after he challenged BNP electoral fraud. But, they say, that was the limit of the trouble.

True, the BNP tries to incite fear. The local authority suspended Richard Barnbrook, a BNP councillor and member of the London assembly, for making up stories about knife crime in the town. BNP announcements that it had discovered a shooting range in a local mosque and £50,000 grants to Africans turned out to be equally phoney.

Given that Britain has had to cope with an unprecedented wave of immigration, and that towns like Dagenham have not only seen the end of secure employment but affordable housing vanish, even the Labour MP Jon Cruddas is surprised that there has not been a stronger backlash. But he and many others continue to worry that, in London, politics is becoming racialised.

In Dagenham, there is the white BNP. In Bethnal Green and Bow, George Galloway won for Respect, a bigoted party dominated by Jamaat-e-Islami, which in its native Bangladesh is regarded by the liberal-minded with fear. South of the river, West African voters are turning to the evangelical Christian Peoples Alliance, which demonstrates against new mosques.

On Thursday night, attention will focus on the politics of the Dagenham estates and others like them when Nick Griffin, leader of the BNP, appears on BBC's Question Time.

As its theme tune jangles out, David Dimbleby could announce: "Joining us tonight from Television Centre, we have Conservative peer Baroness Warsi, Labour's justice secretary, Jack Straw, and making his first appearance on Question Time, Britain's leading neo-Nazi, Nick Griffin." Perhaps he will, but broadcasters have a feeble record of taking on totalitarian movements, and in ways that neither the BBC nor mainstream politicians realise, the ability of democratic Britain to expose sectarianism and call it by its real name will be as much on trial this week as the leader of the BNP.

A media interested in nothing so much as covering media stories will make the programme an event. Dozens of press articles and radio debates have already analysed the BBC's decision to allow the British National party on to its best current affairs show. The London media barely cover the ugly problems of Stoke-on-Trent, Burnley, Oldham, Dagenham and the other depressed areas where the BNP has made gains, but justifies its current focus on itself by insisting that Dimbleby's rigorous interviewing and the tough interventions of the mainstream panellists will expose the BNP.

Sitting in his cluttered office in a rundown parade of shops in Dagenham – only a 15-minute train ride from central London, but a world away – Jon Cruddas doubts it. The leftwing Labour MP has fought the BNP harder than any other politician. It became the second largest party on Dagenham council in 2006, and there is a chance – albeit an outside one – that it could take his parliamentary seat next year. Cruddas and his assistants are engaging in an unglamorous task. By the next election they will have argued with every voter worried about African and Polish immigration into the borderlands of east London and Essex, or bewildered by the collapse of the old certainties of working-class life.

Cruddas dismisses journalists' boasts about the ruthlessness of television's inquisitors as so much wind. Question Time "is just car-crash TV", he says. "He who gets the best soundbite wins. If they were letting Andrew Neil loose on Griffin for an hour, that would be public service broadcasting, but this is pointless. It can only benefit the BNP."

Maybe Neil could give Griffin a hard time, but the precedent set by his fellow broadcasters is not encouraging for those hoping that he will be unmasked on Thursday. The supposedly ferocious Jeremy Paxman turned into Barbara Cartland when he interviewed the then new leader of the BNP in 2001. "Can I ask you a simple question? If one of your children fell in love with a Muslim or an Asian, what would you do?" he began.

"I would be very unhappy about it, because I would have seen two very distinct lines with their own heritage and culture being destroyed," Griffin replied. But, beseeched Paxman, "do you think that's a greater consideration than the fact that they might be in love?" Griffin calmly pointed out that many Asian parents felt the same way as him because "the decision to stay with your own people is a very strong human instinct".

When Paxman pressed again, Griffin concluded by saying: "Well, children are children and adults are adults, and they do what they want." A stumped Paxman said: "Mr Griffin, thank you", and grateful BNP supporters posted the interview on YouTube.

This year Andrew Marr allowed Griffin to get away with saying that a "significant number of blacks and Asians voted BNP", which is not true, and that the party had no problem with blacks and Asians "who have bought into our ways and values, like Trevor McDonald". Needless to add, his pretence that the BNP does not wish to deport Britons with the wrong skin colour wasn't true either. The BNP's constitution says that it wishes to restore "the overwhelmingly white makeup of the British population that existed in Britain prior to 1948" – when the SS Windrush docked at Tilbury, beginning the postwar immigration of blacks and Asians.

Earlier this month, Radio 1's Newsbeat cutely allowed "Mark and Joey, two young guys who are members of the BNP", to imply that Chelsea and England footballer Ashley Cole was not really British. It did not reveal that "Mark" was Mark Collett, the BNP's press officer and an admirer of Nazism, and "Joey" was Joey Smith, who runs the BNP's record label.

It is as if well-paid broadcasters have been cocooned from the dark ideologies that so dominated the 20th century. Radio 1 gives greater latitude to spin doctors from the BNP than spin doctors from the mainstream parties. Marr was not prepared to confront the chairman of the BNP with his party's policy of stripping millions of British citizens of their rights, but was prepared to give credence to false rumours by confronting a Labour prime minister with the accusation that he was taking prescription drugs.

Rolling news and the internet favour glib commentary over serious journalism. Yet the spectacle of broadcasters asking rougher questions of the prime minister and leader of the opposition – who, say what you like about them, do not dream of being the next Adolf Hitler – remains strange. It is not as if the ambitions of the BNP are a secret. The party was born out of the split of the last successful neo-Nazi movement in Britain, the 1970s National Front. The BNP did not represent the breakaway of the NF's moderate wing. In 1985, the courts jailed a founder member, Tony Lecomber, for plotting to blow up the offices of a rival organisation.

Griffin grew up in a National Front family and quickly adopted the Jewish conspiracy theories of traditional Nazism and the white supremacism of the Ku Klux Klan. Not all his preferences were as obvious. He admired the demagogic black separatist Louis Farrakhan for his insistence that blacks and whites could never live together, and the dictatorships of Colonel Muammar Gaddafi and Ayatollah Khomeini for their hatred of Jews. All extremisms, far left, far right and religious fundamentalists, are the same in essence. And today, although the BNP strains at the leash to attack British Muslims, prominent neo-Nazis who grace its rallies will join British Trotskyists in appearing on Press TV, the Iranian propaganda station, and the BNP's foreign affairs spokesman denounces "the warmongers in London and Washington" with all the fervour of Iran's president, Mahmoud Ahmadinejad.

Griffin also admired violence. He joined the BNP after it won a council seat in Millwall in south London. "The electors did not back a postmodernist rightist party, but what they perceived to be a strong, disciplined organisation with the ability to back up its slogan 'Defend Rights for Whites' with well-directed boots and fists," he said.

The byelection was a rare success for the far right of the 1990s. The economy was growing and the country was about to elect Tony Blair. The time when the National Front could win more than 20% of the vote in the Black Country and the East End of London seemed as far away as the three-day week and power cuts. Yet in Europe, parties that had their roots in the fascism of the 1930s were doing well, most notably Jean-Marie Le Pen's National Front in France. Griffin reasoned that, if only the BNP could decontaminate its brand, perhaps it could share their success. He spoke of his plans in April 2000 to the American Friends of the BNP, a group that included David Duke, the then Ku Klux Klan leader, and James W Von Brunn, the white supremacist who shot dead a guard at the Holocaust museum in Washington this year. "The BNP isn't about selling out its ideas, but we are determined to sell them," he explained. Instead of talking about Jewish conspiracies and racial purity, he would use "saleable words such as freedom, security, identity, democracy".

He said that the desire to form a national socialist dictatorship and to force out the descendants of immigrants remained the same; only the means were changing. "Once we're in a position where we control the British broadcasting media, then perhaps one day the British people might change their mind and say, 'yes, every last one must go'. But if you hold that out as your sole aim to start with, you're not going to get anywhere. So instead of talking about racial purity, we talk about identity."

Footage of the event is on the web, but the media do not know or want to know how to deal with a man who fantasises about controlling them.

The difficulties are particularly acute for Question Time. With five panellists and Dimbleby and members of the studio audience all wanting their say, there is no scope for forensic questioning. A performer merely needs to look composed and deliver his lines.

I speak from experience when I say that outsiders – journalists, comedians, celebrity dons – have it easiest. We can engage in a little rabble-rousing, while politicians know that the Westminster press will accuse them of a "gaffe" if they accidentally deviate from the party line. Griffin, who has been practising his sales pitch since he addressed the Ku Klux Klan leadership in 2000, will be composed. He may be surprisingly popular because Question Time cannot just be about racism, antisemitism and links between rhetoric and violence. As a regular panellist put it: "Suppose there is a question on the transport system, and Griffin says 'congestion in our cities is a disgrace that needs to be tackled now', the other panellists can only nod in agreement. They cannot condemn him as a dangerous lunatic."

By this weekend, nervy producers were hitting the phones as they began to realise the 1,001 ways the show could go wrong. One minute, they booked Douglas Murray. He runs the Centre for Social Cohesion, which examines neo-Nazi, Islamist and other extremism in Britain. But he is also from the right, and so, the BBC reasoned, could tell the audience that it was possible to worry about immigration without being compelled to vote BNP. Murray was more than ready to take Griffin on, but the next minute the BBC called back with second thoughts. If he were to say anything in favour of immigration controls, Griffin would look like he was the voice of consensus. As confused call followed confused call, Murray formed the impression the BBC did not know what to do.

Nor do the political parties. Originally, the Conservatives put up Michael Gove, one of their best debaters. Then they decided that, as a British Asian, Lady Warsi would be the ideal face of progressive conservatism and a living rebuttal of BNP prejudice. So she would, had she not run a nasty campaign against the sitting Labour MP in Dewsbury in the 2005 election. In white areas, she declared that she would campaign "for British identity and British citizens" and fight the menace of mass immigration. In Muslim areas, the flag appeared in leaflets in a blood-spattered montage of Tony Blair and George Bush and troops in Iraq, while underneath it she played to religious homophobia by claiming that Labour was allowing children to be propositioned for homosexual relationships.

Jack Straw is a more formidable politician, but as a series of leaks to the Observer in 2006 showed, he spent a part of his time as foreign secretary trying to "engage" with the Muslim Brotherhood, an organisation that, in its origins and policies towards women, Jews and gays, is not so different from the BNP. So assiduous did Straw's attempts at "engagement" become, the British ambassador to Egypt warned him he was engaging for the sake of engagement, and that there was no prospect of Britain being able "to influence the Islamists' agenda".

It is not that Warsi and Straw are as bad as Griffin, but their pasts leave them open to charges of hypocrisy. That their parties have nevertheless chosen them to confront Griffin suggests that they, like celebrity broadcasters, think it is enough to accuse the BNP leader of racism for him to show his fangs to the cameras.

As Thursday night will demonstrate, the rebranded BNP is more sophisticated than that, and fighting it requires principled and hard-hitting politicians who are as able to take it apart in the studios of Television Centre as on Dagenham's council estates.