The British National Party is poised to accept non-white members and candidates of different ethnicities following a legal challenge which accused it of racial discrimination.

BNP leader Nick Griffin indicated that the party will make changes to its constitution after the Equality and Human Rights Commission sought an injunction, claiming the party’s membership rules breach the Race Relations Act.

The party regularly states that it already has a Jewish councillor — Pat Richardson in Epping Forest — but it currently restricts membership to “indigenous Caucasians”, which it broadly defines as Celts and Anglo-Saxons.

Admitting the EHRC move was “a serious threat to our very existence”, Mr Griffin said changes would “stick in the craw of us dedicated nationalists”.

A hearing on the matter at Central London County Court last week has been adjourned until October 15.

Either we shift our position or we will be utterly crushed Nick Griffin

Mr Griffin said the costs of defending the case would cripple the party. “Either we shift our position or we will be utterly crushed. Adapt or die is the only decision left to make, for failure to adapt would lead either to our being bled white through the courts or crushed by new criminal laws. Party unity is priceless, because a party of brothers standing shoulder to shoulder can be persecuted, but it can never be beaten or broken.”

A spokesman for Searchlight, the anti-fascist organisation, said the BNP may have already devised a scheme for levels of membership, meaning a black or Asian person could join but not be allowed to vote on party matters or stand for election immediately.

The BNP’s change of stance came as the BBC confirmed it is likely to invite Mr Griffin to appear on Question Time, following his election to the European Parliament.

The corporation said it was legally bound to treat all political parties registered with the Electoral Commission with impartiality.

A Board of Deputies spokeswoman said: “We do not believe the BBC should provide a platform for the BNP. We were at the forefront of the campaign against them at the European elections. It’s questionable that mainstream politicians who represent us should appear on a platform alongside the BNP.”

Mark Gardner, Community Security Trust communications director, said: “We don’t believe any public money should be used to give a platform to racists, and that includes the BNP.”

But Lucy James, of the Quilliam Foundation counter-extremist think-tank, said Question Time would be a perfect opportunity to “refute” the BNP.

She said: “Politicians, rather than shying away from the BNP, need to arm themselves intellectually against them and publicly challenge their ideology.”

Labour has abandoned its policy that senior politicians should not appear alongside BNP members after the BBC apparently threatened parties which refused to take part in the programme with an empty chair at the table.

The Conservative and Liberal Democrats said a show with the BNP on the panel would be treated the same as any other and senior party members would appear and counter Mr Griffin’s views.

The BNP said it would use the programme to defend itself against attacks from mainstream politicians.

A BBC spokesman said: “Our audiences will make up their own minds about the different policies offered.”