The BBC is to include BNP supporters in the audience for Thursday'scontroversial edition of Question Time when the party's leader, Nick Griffin, will become the first far-right politician to appear on the programme.
Hundreds of party members are understood to have applied to watch the edition when it is filmed at BBC Television Centre in west London. A source said a number would be vetted and allowed to take part.
The disclosure is likely to inflame the heated debate about the corporation's decision to invite Griffin on to the BBC1 current affairs programme – a move anti-fascist campaigners say will confer legitimacy on the party.
It also creates the potential for clashes in the studio between BNP members and anti-racism groups who have also urged supporters to try to join the audience.
The Welsh secretary Peter Hain, who has strongly criticised the BBC's decision to include Griffin, said: "This just reveals what I have said all along. This is not about the BBC exercising its charter duties of impartiality, as they maintain. This is about creating a great big beanfest of a show that rockets their ratings and they walk away leaving the BNP in pole position, absolutely ecstatic that it has received the respectability and credibility it has always craved.
"This is the BBC seal of approval on the BNP – a racist and fascist party – as a respectable party. It stinks."
The application for members of the public to attend Question Time asks: "If there were a general election tomorrow, which political party would you be most likely to vote for?", and gives a list of parties.
It does not include the BNP but does include the choice of "other" and leaves a space for people to write in their allegiance. All applicants are also asked for a phone number, email address and if they fully support their party's leader.
A BBC insider said that despite political pressure over Griffin's appearance, the corporation has to be seen to be impartial and ensure a balanced audience, "including BNP members". spokesman for the corporation declined to comment on the vetting issue. The BBC is keen to avoid a repeat of the furore over the Question Time programme broadcast two days after the September 11 terrorist attacks in which a US ambassador to the UK, Philip Lader, came under verbal attack from audience members expressing anti-American sympathies. The BBC received 600 complaints and the former director general Greg Dyke publicly apologised to Lader a couple of days later.
With a political row hanging over the programme and demonstrations by anti-fascist campaigners expected at Television Centre, the BBC is taking extra care vetting audience members and carrying out additional security checks. No journalists are being allowed to watch the filming and the programme – which is usually pre-recorded – is being filmed earlier than usual on Thursday afternoon to give leeway to edit it should there be a disturbance.
The BBC's corporate security department and the police have been liaising over security issues. Anyone who has got into the audience illegally and circumvented the security checks on Thursday will be asked to leave.
The BBC is still, however, facing the prospect of an eleventh-hour challenge by Hain, who has appealed to the BBC Trust to block Griffin's appearance because the BNP is not a "lawfully constituted political party".
A spokeswoman for the trust said it would discuss Hain's appeal and "decide whether or not it would be appropriate to hear" it. The trust could "in principle" intervene ahead of the broadcast but the spokeswoman said that, in practice, it never interferes in programme content before transmission.