By Iain Watson
BBC political correspondent
BNP leader Nick Griffin says some of the leaked details are incorrect
We all know extreme sports can be edgy, exciting and exhilarating - but for an edge of the seat experience, extreme politics tends to triumph.
Whether left or right, fringe politics is often characterised by factionalism, schisms, and real or imagined betrayals.
The BNP, of course, would claim it is not on the extreme fringe of politics, and its leader Nick Griffin says that is possibly the reason his membership lists have been leaked.
As the party, in his eyes, moves towards the mainstream, the extremists feel marginalised and it was one of those disgruntled former members he blamed this morning for the leak of the November 2007 membership list in defiance of a court injunction.
However, subsequently some in his party are pointing the finger at Labour activists.
But whoever leaked the information, Mr Griffin is now trying to snatch victory from the jaws of embarrassment.
He points out that a previous leak of members' names in London did the party nothing but good.
What could do more to distance the party from its image as a reservoir of white working-class discontent than a ballerina - Simone Clarke - with a Cuban boyfriend espousing the party's anti-immigration policies?
Most of the membership details that have been leaked this time do not include people's professions - in fact the catch-all description "activist" crops up with remarkable frequency.
But the BNP leadership will be pleased to align themselves with a director of an IT company; a computer manufacturer and a web designer - all jobs which suggest the party has a future and isn't mired in the past.
Quite frankly what is there to be afraid of, to hell with the cowards that quiver over this. BNP= British Nationalist and Proud!
There are a few alleged professions that may still raise eyebrows - for example, a karate instructor who says he is no longer required.
And there is a CCTV installer whose skills could perhaps have been used to improve the party's internal security.
While a leak of this kind might improve the BNP's image overall, not every individual party member is too keen to sacrifice their privacy and possibly their personal security for the greater good of their organisation's standing.
The BNP's regional organiser in Northern Ireland has apparently advised members to increase security measures because of the potential risk of attack from dissident Republicans.
The leaked list names 39 people with Northern Ireland addresses and two with addresses in the Irish Republic. The BNP previously called for the death penalty for IRA terrorists.
But apart from personal security, there is also a question of job security.
The list apparently includes serving police officers who would be banned from BNP membership.
It has been reported that investigations have begun into one person on the BNP list who is said to be a serving police officer on Merseyside.
There is also a prison officer on the list and the Prison Service asks all recruits to confirm they are not BNP members.
If they sign up to BNP membership after joining the prison service, they will be asked again about their political views if they apply for promotion.
There is at least one teacher on the list and the teaching union NASUWT is campaigning to ban BNP members from the profession.
The BNP, as a legal political party, denounce this as discrimination and say they are not a racist party but a party concerned about immigration and in favour of voluntary, not compulsory, repatriation of non-European immigrants.
Nonetheless, some of those on the list who were contacted by the Times newspaper said they were worried about their job, and some of those contacted by the BBC have said the details on the membership list are wrong.
Nick Griffin did confirm the list was largely accurate but gave himself a get-out clause.
He said some non-members' names had been added to create mischief.
That would allow any genuine members contacted by the media to deny membership if they were in a sensitive profession, should they be so inclined.
But there are also defiant messages on the BNP website.
Just one example reads: "Quite frankly what is there to be afraid of, to hell with the cowards that quiver over this. BNP= British Nationalist and Proud!"
Nick Griffin says he will go to court if necessary to protect his members' human rights, to prevent any further leaks and to try to stop further dissemination of personal information.
So it remains to be seen just how many of the 12,000-plus BNP members are as proud of their affiliation publicly as they are when they hold their meetings.