A Dungannon man identified on a leaked list of British National Party members has described how he was "duped" into joining the organisation.
Harry Martin (64), who served as district commander of the fire brigade until retiring 15 years ago, admitted making a one-off payment to the far-right extremist party and said he bitterly regretted doing so.
Mr Martin, who has fought for years for a medal for firefighters who served bravely during the Troubles in Northern Ireland, said he joined the BNP seven years ago because they promised to support his campaign.
But after a year the party had failed to maintain its pledge of support, and Mr Martin cancelled his membership.
He said he had not been involved in any way with the BNP since and insisted he did not support their extremist policies.
"Seven years ago I gave a small donation after being backed into a corner," Mr Martin said. "It was a mistake that I thought would help with the medal issue and I have been nowhere near them since.
"I'm the same Harry Martin that everyone knows. I only joined in a panic and to get something done which was right. The BNP told me that they could help but they didn't do anything. I was duped into joining."
Around 13,500 names and home addresses of party activists, members and donors were posted on to an internet website last Monday evening, including 39 people with addresses in Northern Ireland.
The list also identifies a person with an address in Omagh who, it says, is a party "activist". Another person with an address in Fintona is also identified, along with a note which says "awaiting family details".
Party officials have confirmed that the list, which is reported to detail the BNP's entire membership, was genuine.
It identifies thousands of people as secret supporters of the party and exposes many to the risk of dismissal from work, disciplinary action or vilification.
It is thought that the list may include the names and addresses of people who have expressed an interest in joining the party, but have not signed up, as well as lapsed members such as Mr Martin.
He said he joined on a one-off occasion because he believed it would help progress his long-term campaign for a fire service medal.
"I spoke to every major political party in Britain and Northern Ireland and none had any time for me at all," he added. "At the time the BNP was campaigning in Dungannon and it was a party I didn't know much about.
"They said they would take the medal issue on board but after a year they hadn't done anything and I just resigned from them.
"I paid my one year's dues and just called it a day. That was me finished with the BNP."
Now he is worried that the leak could damage his name in the South Tyrone area and insists that joining the BNP was a mistake which he deeply regrets.
"I'm not an evil man," he added. "I went to them for urgent help because no-one else was helping me.
"I joined with the good intention of making progress on the fire medal issue as every other party had turned their back on me.
"Harry Martin hasn't changed and this was a mistake which I made years ago and which I regret. I'm not a bigot and I have no issues with any member of society. I wish everyone the best."
Nick Griffin, the BNP's leader, claimed that he knew the identity of the person who published the list, describing him as a "hardliner" senior employee who left the party last year.
Deputy leader Simon Darby said: "If we find out the name of the person who published this list it will turn out to be one of the most foolish things they have done in their life."
But Mr Griffin insisted those words did not represent a threat of violence but the reality that the person faced prison for breaching a High Court injunction.
The BNP's regional organiser, Kieran Dinsmore, said Northern Ireland members were being advised to "take reasonable steps" to increase their personal security.
According to its constitution, the BNP is "committed to stemming and reversing the tide of non-white immigration and to restoring, by legal changes, negotiation and consent the overwhelmingly white makeup of the British population that existed in Britain prior to 1948."
The BNP also proposes "firm but voluntary incentives for immigrants and their descendants to return home."
It advocates the repeal of all anti-discrimination legislation, and restricts party membership to "indigenous British ethnic groups deriving from the class of 'indigenous whites'."
The BNP has been shunned by mainstream politicians and has been strongly criticised by British political leaders including Gordon Brown, Tony Blair and David Cameron.