The British National party is being taken to court over claims its membership criteria breach human rights law.

The Equality and Human Rights Commission said it had issued county court proceedings against the party leader, Nick Griffin, and two other officials today over the BNP's membership rules.

The party's constitution limits members to people who are "'indigenous Caucasian' and defined 'ethnic groups' emanating from that race".

The commission first wrote to the BNP in June stating that it believed the party is in breach of the Race Relations Act. The far right organisation responded by saying it intended to clarify the word "white" on its website.

However, the commission said today that it believes the BNP is still discriminating against "potential or actual members on racial grounds".

"The BNP has said that it is not willing to amend its membership criteria which we believe are discriminatory and unlawful," said John Wadham the commission's group director.

"The commission has a statutory duty to use our regulatory powers to enforce compliance with the law so we have today issued county court proceedings against the BNP."

Wadham said the BNP could still avoid court action if it moved quickly to change its membership rules.

However, a spokesman for the party said it intended to fight the move, claiming the action was politically motivated.

"It is strange that this is happening now when these rules have been in place for a long time," said the BNP's deputy leader, Simon Darby. "And we certainly resent the fact that some unelected body which is 70% ethnic can accuse us of racism."

The commission said it had decided not to take action on two other grounds set out in its original letter to the BNP after the party agreed to comply with the law.