Just a few years ago, Nick Griffin, leader of the far-right British National Party (BNP), can only have dreamed of being invited on to the nation's leading political panel show.

But now he is due to appear on the BBC's "Question Time" Thursday night, commentators are asking what impact it will have on the BNP's fortunes -- and what it means for Britain's mainstream parties, who are fielding speakers alongside Griffin.

A hate figure for the political establishment, Griffin was invited on the show because he has led the BNP to its strongest-ever position, with two members of the European Parliament (MEPs) including him, one member of the London Assembly and around 55 local councillors.

He has thanked the BBC for inviting him, telling the Times:"The huge furore that the political class has created around it clearly gives us a whole new level of public recognition."

His opponents, though, are hoping this will be a good opportunity to show up the BNP's policies, which include stopping all immigration.

Fellow guests will include Justice Secretary Jack Straw. Labour has previously declined to debate with the BNP but Straw -- whose constituency has a large Muslim population -- says he is now determined to fight back.

Straw is going head-to-head with Griffin shortly after Labour launched a drive to target the "bullies and boot boys" of the BNP at the next general election.

Research suggests many BNP voters are disillusioned, white working class ex-Labour voters worried about the impact of immigration on employment and housing.

Some commentators point to Tuesday's clumsy rebuttal of criticism by four retired senior military figures that it was trying to "hijack" the military's reputation for its own ends as a sign of what else could go wrong for the BNP.

Griffin compared the retired top brass to Nazi-era generals hanged after the Nuremberg trials which followed World War Two.

But there are other warnings that the format of "Question Time" is fraught with danger for those hoping to use it for Griffin-bashing.

Because it features five public figures talking about a wide range of current issues, Straw and others may only have limited opportunities to attack BNP policies.

One expert has even suggested the "Question Time" appearance could be a turning point for the BNP.

Jim Shields, associate professor in French studies at Warwick University, compares Griffin's position to that of French far-right leader Jean-Marie Le Pen, who appeared on a leading current affairs show in 1984 which sealed his reputation.

Shields said the appearance helped Le Pen, who came second in France's 2002 presidential election, shed his"bogeyman" image, while boosting membership and support for the party.

"In his autobiography, Le Pen would point to that TV programme as the start of his political rise, calling it 'the hour that changed everything'," the professor said.

He added that Griffin seems to anticipate "a similar effect from his appearance on 'Question Time'".

The appearance may end up being a dream for Griffin and a nightmare for his opponents. Or maybe not. All eyes will be on BBC1 from 1035 pm.

In this blog, journalists of global news wire AFP blog about the news they report and the challenges they face covering events from Baghdad to Beijing, the White House to Darfur. Katherine Haddon is a correspondent in AFP's London bureau.