By James Hardy
BBC News political correspondent
Open rebellion is being threatened against the leader of the British National Party, Nick Griffin, from dozens of senior activists.
BNP leader Nick Griffin is accused of "behaving like a dictator"
The party has retaliated by expelling two senior members, who it accuses of plotting a coup.
BNP officials Sadie Graham and Kenny Smith were kicked out after they were critical of Mr Griffin's style.
They have now set up a rival faction, supported by up to 60 senior members. The BNP leadership denies it is split.
The outbreak of faction-fighting could not come at a worse time for the BNP. The party is hoping to make a breakthrough in the London assembly elections next May and cannot afford to appear split.
The row centres on the activities of Ms Graham, the BNP's former group development officer, and Mr Smith, former head of administration.
They were accused of "gross misconduct" after it came to light the party said that they were masterminding a blog site critical of Mr Griffin and demanding the sacking of senior officials Mark Collett and Dave Hannam.
A transcript - said to be of a telephone conversation between three rebels about the blog site - has been published on the official BNP website. It is unclear how it came to be recorded.
The website further alleges they had been illegally hacking into email accounts of BNP members, including Mr Griffin.
In response to this "treasonous behaviour" the party set up an Intelligence Department, headed by a former South African policeman, to track down the source of "leaks and misinformation" aimed allegedly at helping political opponents.
But the rebels say all they are doing is trying to defend the reputation of the BNP.
They cast themselves as modernisers frustrated at the failure of the party to confront its problems. The last thing they want, they insist, is to split the party or to lead a coup.
They have now set up a "Real BNP" faction. It appears to have the support of up to 60 senior party members - ranging from the leader of the BNP youth wing and regional and city organisers to councillors, fundraisers and activists.
Ms Graham and Mr Smith are urging activists not to leave the party but to resign the whip on councils and stand as "independent nationalists".
They are accusing the leadership of "arrogance, lies and incompetence" and one blogger on the site says Nick Griffin is behaving like a dictator.
Another says he is making "Stalin look like a moderate".
Ms Graham claims that the party's "Security Department" broke into the home she shares with another prominent activist - ironically, the Head of Security Matt Single - and removed her computer and other personal information.
The party says it was let in by a "key holder" and simply took away its own property.
The combined object of the rebels' anger are Mark Collett, the Leeds-based right-hand man of Mr Griffin, and Dave Hannam, a party treasurer.
According to the rebel blog, Enough is Enough, Mr Griffin and other leaders have had to endure at least two stormy regional meetings since the expulsions on 9 December.
The BNP's deputy leader, Simon Darby, has told the BBC that the row will blow over by Christmas and that the vast majority of the party's 10,000 members are behind Mr Griffin's leadership.
He denies the BNP is irrevocably split - claiming it is simply going through a cyclical period of "tension" which has characterised the party's history.
Many in the mainstream parties at Westminster, though, are hoping the bust-up could presage the sort of division which destroyed the old National Front and left far-right politics in the doldrums for more than a decade.
Whether that is anything more than wishful thinking remains to be seen.