At first glance the Trafalgar Club - with its annual dinner commemorating the famous sea battle - sounds like a heritage society wanting to honour one of Britain's national heroes.
Members of The Trafalgar Club get a chance to dine with Nick Griffin
For just £15 a month minimum donation, members receive a newsletter and a free ticket to its annual dinner.
Men get a tie with "England Expects" - the first two words of Nelson's rallying signal at the battle - emblazoned on it while women receive a personal organiser.
The club could be a gathering of naval historical enthusiasts - the reality is different.
Those who attend the annual dinner are addressed by Nick Griffin, chairman and leading light of the British National Party.
Billed on the party's website as its "elite fund raising group", the club is a channel for well-heeled BNP supporters to give financial aid to the party without having to be listed as an official donor.
The website tells would-be members: "You do not need to be a member of the British National Party to join the Trafalgar Club.
"The government currently bans many civil servants from joining the BNP so the Trafalgar Club is a great way of demonstrating your patriotism and making sure you keep your job."
It adds: "After many years of running on shoe-string budgets, the BNP has learned how to stretch a pound as far as it will go!"
However, a BBC File On 4 investigation has heard other claims about the party's finances.
The BNP denies it has broken party funding rules
Former party treasurer John Brayshaw refused to sign off the party's accounts because he claims he was not given the access to all the records he needed to see.
In 2005 he wrote to the Electoral Commission, the body which oversees political party finances, saying that he resigned as BNP treasurer. He alleged a number of irregularities had come to light including missing invoices and receipts from the Trafalgar Club.
In his letter, Mr Brayshaw said current party treasurer John Walker and his deputy David Hannam visited his home for a week to complete the accounts.
He said he did not help them but claimed he witnessed some unusual activities, namely the shredding of a large number of documents and invoices.
Mr Brayshaw said he was told to burn the shredded documents, but kept them because he felt something improper had taken place.
A black bin bag containing the documents has been handed to File On 4.
It contains fragments of cheques, train tickets, receipts and invoices.
Some of the fragments carry the names of Nick Griffin, his parents and even the Trafalgar Club.
One unshredded item is a petrol receipt with the name Excalibur - the title of the party's merchandising arm.
Under tax regulations all financial records should be kept for six years.
The Electoral Commission said it had no reason to believe a breach of the party funding law had taken place.
Current BNP treasurer John Walker dismissed Mr Brayshaw's allegations as pure fantasy.
He said Mr Brayshaw had failed to make the books balance and had left the party's accounts in a mess.
Mr Walker said the shredded material included material such as "draft accounts that may have errors in dates and things like that. Because you are trying to reconcile the accounts, of course you shred documents."
Documents John Brayshaw claims he was ordered to shred have been handed to File On 4
Confronted by the BBC with some of the shredded material, Mr Walker said they contained working copies of printouts of the BNP accounts and bounced cheques.
He added: "What you've got in front of me here is clearly very weak evidence and the BBC is clutching at straws."
Among other questions raised by File On 4 are whether the BNP breached party funding rules by not declaring the name of a donor who gave £20,000 to the party. The rules say all donors who give more than £5,000 should be identified.
When leader Nick Griffin was cleared of race hate charges in November 2006, he claimed the party had just received its largest ever donation.
BNP member Sharon Ebanks told the BBC she was personally thanked by a party official for collecting the £20,000 donation via her internet fund-raising.
Ms Ebanks told File On 4 that the party informed her the donor's cheque was genuine and he should be made an honorary life member.
The BNP strenuously denies that it has broken any rules. It claims that the cheque in fact bounced and therefore did not need to be declared.
Labour MP for Dagenham Jon Cruddas has already raised the issue of BNP finances in Parliament, and presented the Electoral Commission with a 20-page dossier just before Christmas.
He said: "What this investigation for File On 4 is identifying is much more significant than any of the charges I was laying before the parliament - namely a systematic series of financial irregularities.
"And this cannot be laid to rest without the most thorough of investigations by the Electoral Commission."
Hear the full story on BBC Radio 4: File On 4 Tuesday 12 February at 2000 GMT, repeated Sunday 17 February at 1700 GMT or online at File on 4 website.