Under the Political Parties and Referendums Act 2000 all parties need to confirm their registration details with the Electoral Commission.
But despite having six months notice, the BNP missed the deadline.
BNP spokesman Stephen Squire said: "It's the first I've heard of it - it's obviously an oversight."
But former BNP leader Nick Griffin, who was expelled by the party in 2014, told LBC Radio the mistake was "either incompetence or it's a combination of a deliberate wrecking job which has been going on over the last year or so."
However, BNP chairman Adam Walker, in a fundraising email to party supporters, said the "media frenzy" created by the technical oversight "proves how relevant and newsworthy the BNP is".
By law, the Electoral Commission has to remove from its register any political party that fails to submit its details.
Such a waste?
The BNP's statement of accounts were due on 7 July 2015, but despite a six-month window, the party had still not paid up by the final deadline on 7 January 2016, forcing the commission to take action.
Removal from the register means BNP candidates cannot use the party's name, description or emblems on ballot papers at elections.
But, a commission spokesman said if the party re-registered in the near future, its candidates would be able to stand under the BNP banner at this May's local elections.
However, if they wish to stand before the registration is considered, BNP candidates will have to stand as independents.
Mr Squire suggested the party had too much to lose to let its registration lapse further.
"After battling for 30 years to get the debate on immigration going, we don't want to waste it on a technicality," he said.
Party names and identities are protected for two years under the 2000 Act to prevent other parties using them.
Nick Griffin stepped down as BNP leader in July 2014 after 15 years at the top. His decision came after he lost his seat in the European Parliament and the party saw its vote collapse in that year's local elections.
But months of infighting followed and Mr Griffin was expelled from the BNP amid accusations that he had tried to "destabilise" the party.
The British National Party risks being unable to stand for election - because it failed to pay its annual £25 registration fee.