KEN LIVINGSTONE, Labour’s candidate in the coming London mayoral elections, and Green Party candidate Jenny Jones, last week withdrew from a BBC London mayoral debate because the British National Party candidate was to be taking part.
And spokesperson for Tory Boris Johnson said he had never confirmed his involvement, but would also "not share a stage" with the BNP.
Liberal Democrat candidate Brian Paddick has withdrawn too, but a spokesperson said it was not a result of the BNP's participation.
The BBC said it was committed to giving the BNP "proportionate coverage".
Announcing his withdrawal, Livingstone said: "The far right want to destroy our democracy and stand for the elimination of our basic rights. They cannot be treated as a legitimate part of politics.
"We have been in negotiation about a debate with the main candidates for BBC London 94.9 – but only now have we been informed that the BNP had been invited to take part in this debate.
"I will not share a platform with the BNP and it is a point of principle to me that I never will do."
A Green Party spokesperson also said Jones "would not share a platform or a debate" with the BNP's candidate Carlos Cortiglia.