In a letter from the Equality and Human Rights Commission, Nick Griffin, the BNP leader, was told that he had less than a month to provide written undertakings that the party would abide by race relations legislation.
John Wadham, legal director of the Commission, said that the watchdog was concerned that the BNP’s constitution and membership criteria could be in breach of the law.
Party membership was said by the Commission to be restricted to those with white skin and a small number of other ethnic groups.
In a statement, the watchdog added: “This exclusion is contrary to the Race Relations Act which the party is legally obliged to comply with. The Commission therefore thinks that the BNP may have acted, and be acting, illegally.”
There were further concerns over the requirement on new staff to be party members, and fears that elected BNP representatives would be unwilling to provide help and support to non-white constituents.
If the BNP does not provide written undertakings by July 20 that it will make the changes required by the Commission voluntarily, then the watchdog said that it would apply for a legal injunction which would compel them to comply.
Any breach of a court order would be a criminal offence and leave the party’s leaders open to prosecution.
Mr Wadham said that the Commission had a legal duty to ensure that political parties were not breaking the law by discriminating against ethnic minorities.
He added: “The legal advice we have received indicates that the British National Party’s constitution and membership criteria, employment practices and provision of services to constituents and the public may breach discrimination laws which all political parties are legally obliged to uphold.
“Litigation or enforcement action can be avoided by the BNP giving a satisfactory response to our letter.”
The BNP has been ordered to provide a written undertaking that it will not breach race relations laws in its “employment, recruitment, procedures and practices”.
On the BNP’s website, applicants for party jobs are asked to supply a membership number. The Commission said that this amounted to a potential breach of laws which ban parties from refusing employment on the basis of non-membership of an organisation.
Earlier this month, two BNP members, including Mr Griffin, were elected to the European Parliament, the highest office enjoyed by party representatives to date.
The Commission said that it was concerned that they and the party’s local councillors did not intend to provide their services on an equal basis to all constituents irrespective of race or colour.
A spokesman for the BNP said that the party would not be commenting.
[Editors Note: The letter from the so-called Equality and Human Rights Commission can be read or downloaded as a PDF document here.]