The British National party faces the prospect of renewed legal action from the government's equalities watchdog over allegations that it has failed to remove potentially racist clauses from its constitution. The court case could potentially see the BNP's leader, Nick Griffin, jailed or fined for contempt of court, or see party assets seized, lawyers believe.

It caps a miserable couple of weeks for the BNP. Griffin came third in the parliamentary vote for Barking, a constituency the BNP had targeted heavily, while his party lost all 12 of its seats on Barking and Dagenham council. That followed a disastrous election campaign in which the BNP website was taken down by its designer, the party's publicity director was arrested on suspicion of threatening to kill Griffin and a London candidate was caught on camera fighting in the street with a group of Asian teenagers.

The BNP constitution was challenged in court last year by the government's Equalities and Human Rights Commission. In March, Judge Paul Collins ruled that even after the BNP lifted a direct ban on non-white members, the revised document was indirectly discriminatory because it required applicants to oppose "any form of integration or assimilation of ... the indigenous British", something the EHRC argued could not be endorsed by those in mixed-race relationships.

The constitution additionally required new members to submit to a two-hour vetting visit at their home by a pair of BNP officials, a clause Collins ruled could be seen as intimidating for non-white applicants. He ordered both offending sections be removed.

Following the ruling, Griffin redrafted the BNP constitution, something the party's rules allow him to do without consulting members. However, copies of the new version – officially known as draft 12.2 – show that both clauses have not been removed but moved and slightly amended. The home interview clause returns in near-identical wording as the "annual visit criteria", without which new members cannot attend meetings or vote on party matters.

"This seems like a slightly hapless attempt to get round the injunction by moving the offending section to a different part of the constitution," said Paul Epstein QC from Cloisters Chambers in London, a specialist in discrimination law. "There seems to be no doubt that what they have done goes against the spirit of Judge Collins's ruling at the very least. They're taking a real risk of being found in contempt of court. This is particularly the case for Griffin, given this role he has in changing the constitution."

The section relating to the "indigenous British" remains in the new constitution, under the heading "Temporary amendment". Gavin Millar QC, a specialist in election and discrimination law from Doughty Street chambers, said this appeared to breach the court decision. "The ruling made it quite clear that the reference to 'indigenous British' was discriminatory and had to be removed but the BNP has included it, saying it is only being temporarily removed pending a successful appeal, at which point it will be reinstated. This is a clear breach," he said.

The home visit clause had been slightly reworded but "it is in substance the same", he said, adding: "The approach they have taken is both a civil and criminal breach of the order and I think in the end, unless the courts or the commission give up, which I don't think they will, the BNP and Griffin will in the end face contempt proceedings and possible imprisonment."

Any EHRC action will have to wait until a government is formed, as until then its activities remain constrained by Cabinet Office guidelines on the behaviour of public bodies during election campaigns. An EHRC spokesman said: "At the time of the court ruling, we said that the commission would monitor the BNP's compliance with the ruling. We are currently looking into this matter."

The EHRC is understood to have written to the BNP outlining its concerns about the new constitution and is awaiting a reply. The BNP did not respond to a request for comment.