Edgar Griffin said his expulsion was 'knee jerk'
BBC Political Correspondent Shaun Ley examines what damage - if any - the row will cause the Conservative Party and Iain Duncan Smith's leadership ambitions.
The Conservative Party's decision to expel Edgar Griffin because of his links with the BNP indicates the degree of embarrassment the case has caused.
Mr Griffin had been a member of the party since the 1940s.
He was until today deputy chairman of Montgomeryshire Conservative Association.
One senior member confirmed to me today that it was widely known Mr Griffin's son Nick was the leader of the British National Party.
Tory relief
Until now, though, Edgar had "kept the BNP at arm's length."
Conservative Party officials in London will be relieved that, under the reforms introduced by William Hague, they did have the power to act against him.
In the past, it was extremely hard to remove members because they joined only a local association; the Conservative Party as such did not legally exist.
But Mr Griffin's remarks on radio and television today - suggesting that Mr Hague has wanted asylum seekers placed in concentration camps, and saying the two parties' policies on immigration were similar - opened him up to expulsion for bringing the party into disrepute.
Officials at Smith Square in London will want to know why Welsh Conservatives didn't know - or, if not, didn't care - about Mr Griffin's connection to the BNP.
The most bizarre aspect of this story is that Edgar Griffin's wife Jean actually stood for the BNP against the man he's now supporting for the Conservative leadership.
Mrs Griffin was the BNP candidate in Chingford and Woodford Green at the general election.
Grand title
For Mr Duncan Smith, the damage is likely to be peripheral.
He seems to have acted against Mr Griffin as soon as the allegations emerged.
His campaign may be regretting their foolishness in giving those volunteering their support the rather grand title of 'vice-president' when their names appeared on campaign literature.
Mr Griffin's involvement in the Duncan Smith campaign was negligible. In future, other such volunteers are likely to find their names scrutinised more carefully before they are used.
He's accused Kenneth Clarke's campaign of trying to smear him.
The Clarke team have wisely not commented, knowing their involvement could prove counterproductive.
But they'll be quietly pleased at anything that supports their argument that a Duncan Smith leadership would lead the party further to the right.
The unlicensed freelance operation by Clarke supporter Steve Norris is intended to heighten that claim.
'Smear' accusation
Mr Norris, of course, is no fan of the man they call IDS - the Tory right deserted his first choice for leader, Michael Portillo, who shared Mr Norris's view of the way the party should go.
By accusing his rivals of a 'smear', Mr Duncan Smith may have overplayed his hand.
As the wounded innocent, he would have done better to emphasise his own firm action in dealing with the problem, rather than trying to blame anyone else.
That still may not make much difference, though. Many of the party's members have already sent back their ballot papers.
For all we know, the Conservative leadership contest could already be over.