For Mr Duncan Smith, the damage is likely to be peripheral

More worrying for the Tories is the fact that Mr Griffin was allowed to hold office in the Conservative Party of Wales.

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.

The Clarke team have wisely not commented

Yet Mr Duncan Smith shows signs of being rattled.

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.