Prime Minister Gordon Brown's Labour Party government says it is appalled that the far right British National Party will get such high-profile exposure to millions of viewers. The BBC, however, says as a publicly funded broadcaster it must cover all political parties that have a national presence.
"It's not for the BBC to make decisions about what parties it does and doesn't like," a BBC spokesman said Tuesday on condition of anonymity in line with company policy. "That, quite rightly, is a decision for the electorate."
The BNP, which opposes immigration and says it fights for "indigenous" Britons, wants to become a force in British politics.
Although it isn't likely to gain a seat in the national Parliament because of Britain's first-past-the-post electoral system, the BNP serves on several city councils and made an electoral breakthrough in June, when it took about 6 percent of the British vote in European elections, winning two EU parliament seats.
On Thursday, BNP leader Nick Griffin is scheduled to appear on the BBC's flagship political debate show "Question Time" - a highly valued imprimatur of political respectability.
A senior Cabinet minister, Justice Secretary Jack Straw, is supposed to be on the same programme, where panelists are questioned on current affairs by a studio audience.
The far right party is so pleased with the invite that it is counting down the seconds until the broadcast on its website.
The government and anti-racist groups say the invitation to Griffin legitimises fascist views, and protesters have vowed to picket Thursday's taping at the BBC's West London studios.
Welsh Secretary Peter Hain - a former anti-apartheid activist - has called on the BBC to drop Griffin from the programme, saying the party is "an unlawful body" because historically it has not allowed nonwhite people to be members.
Last week the BNP agreed to change its constitution to accept nonwhite members after it was taken to court by the Equality and Human Rights Commission.
The BBC says it is bound by its public-service mandate to give the party a platform. In a letter to Hain, BBC director-general Mark Thompson said "it remains the BBC's obligation to scrutinize and hold to account all elected representatives and to do so with due impartiality."
The BNP has benefited from a deepening cynicism toward mainstream politics in Britain. The party made its biggest electoral gains in working-class Labour strongholds, among voters angry at rising unemployment and a scandal over lawmakers' expenses.
All the mainstream parties were tarnished when data leaked to a newspaper earlier this year showed that legislators had submitted substantial claims on the public purse for everything from pornography to chandeliers and moat-cleaning.
The BNP has tried to capitalise on its outsider, underdog image, linking itself to Britain's wartime "Blitz spirit" and the armed forces, which have suffered hundreds of deaths in Iraq and Afghanistan and are held in high regard by most Britons.
The party has used military symbols such as wartime leader Winston Churchill and a Spitfire fighter plane - under the slogan "Battle for Britain" - in its campaign literature.
On Tuesday a group of retired military commanders accused the party of hijacking military symbols for "dubious ends."
Four retired generals, including former army chiefs Gen. Mike Jackson and Gen. Richard Dannatt, signed a letter saying extremists and racists "are fundamentally at odds with the values of the modern British military." They called on "all those who seek to hijack the good name of Britain's military for their own advantage to cease and desist."
The generals' letter is part of a campaign against the BNP by military veterans under the slogan "There's Nothing British about the BNP." The campaign, whose supporters include thriller writer Andy McNab, has links to the opposition Conservative Party.
On the campaign's Web site, McNab - the pseudonym of a Gulf War veteran of Britain's special forces - has accused the BNP of racism and of "taking advantage of what our troops are doing" in both Iraq and Afghanistan.
Griffin insists the party is popular among rank-and-file soldiers, claiming soldiers had told him that "almost everyone ... fighting in Afghanistan vote for the British National Party."