**Protesters are expected to picket BBC Television Centre in London later ahead of the appearance of BNP leader Nick Griffin on Question Time.**Cabinet minister Peter Hain’s appeal to the BBC Trust to stop Mr Griffin appearing was rejected on Wednesday.
The trust said it was a “question of editorial judgement” whether it was appropriate for the BNP to appear.
But BBC head Mark Thompson said the case against having the BNP on Question Time is “a case for censorship”.
Writing in Thursday’s Guardian newspaper, Mr Thompson added only governments could decide which organisations should be banned from the airwaves.
The BBC Trust has asked Mr Thompson to ensure the pre-recorded programme was within BBC guidelines.
The decision to allow Mr Griffin, whose party won two seats in the European Parliament in elections in June, has prompted an outcry among anti-fascist protesters.
‘Unlawful body’
The BBC says it is obliged to “scrutinise and hold to account all elected representatives and to do so with due impartiality”.
“Question Time is an opportunity for the British public to put questions to politicians of every ideological hue”
BBC director general Mark Thompson
The BBC’s director general Mark Thompson argued that where organisations were deemed to be “beyond the pale” they were proscribed and/or banned from the airwaves by - and only by - governments.
Question Time “carefully” studied the support gained in elections by each of the parties before deciding who to invite and how frequently, Mr Thompson wrote in the Guardian.
“Question Time is an opportunity for the British public to put questions to politicians of every ideological hue. Politicians from the UK’s biggest parties appear most frequently, but from time to time representatives of parties with many fewer supporters… also take their seats on the stage,” he said.
“It is for that reason - not for some misguided desire to be controversial, but for that reason alone - that the invitation has been extended.”
Mr Hain, a prominent anti-apartheid activist in his youth, had argued that the decision should be re-examined following a court case about ethnic restrictions on the BNP’s membership rules.
The party has agreed to amend its constitution after the Equalities and Human Rights Commission sought an injunction, claiming the BNP was breaking the Race Relations Act by restricting membership to “indigenous Caucasian” people.
“It gives them the legitimacy, the respectability they crave from the BBC and that is what’s shameful in my view”
Peter Hain
Mr Hain argued that made it an “unlawful body” which should not be treated the same as “any other democratically elected body”.
But the BBC said the case did not “legally inhibit” them from allowing Mr Griffin on the programme.
Speaking later Mr Hain said he objected to the BNP “appearing just like any of the other parties”.
“It gives them the legitimacy, the respectability they crave from the BBC and that is what’s shameful in my view.”
BBC Trustee Richard Tait said: "We have decided it would be wrong for the Trust to intervene in a programme not yet broadcast - even one as plainly controversial as this.
“To do so would undermine the editorial independence of the BBC - something we are strongly committed to preserve.”
BNP spokesman Simon Darby said the party would use its own security to get Mr Griffin safely inside the building and there would be no counter-demonstration by the BNP.