She has backed out of her first scheduled public appearance at a teachers' union following the sacking of NATFHE's general secretary, John Akker, for alleged inefficiency.
He was suspended last week and accepted early retirement with a package understood to be as much as #163;80,000.
Instead of attending the conference, Lady Blackstone will send a video to be played back to delegates. She is understood to be unwilling to become embroiled in events at a union that has been split by the deposing of Mr Akker, and would not even agree to a live video link.
The snub is all the more embarrassing since ministers said they would make themselves available to everyone. Three, including Education and Employment Secretary David Blunkett, gave lengthy keynote speeches to meetings for Adult Learner's Week this week.
A NATFHE spokesman denied that the union had been snubbed. "It was always going to be tight to make the journey to Scarborough and back," he said.
Only three days ago, however, Lady Blackstone was discussing details with conference organisers.
While some say they are delighted with the removal of Mr Akker, rank-and-file members in the Wirral, where a large section of a college is under threat of closure, are demanding that he lead a delegation to Government.
Their campaign has been taken up by Labour MP Angela Eagle, who is demanding a full ministerial review. David Blunkett, the Education and Employment Secretary, is understood to be willing to receive a delegation. The NATFHE branch were so impressed with Mr Akker's role in the dispute that they want him to lead it.
The suspension has sent shock waves through NATFHE. Employers in the Association of Colleges are to withdraw from all talks with the union.
Friends of Mr Akker, who is refusing to comment, says he is seeking legal advice on the way the union dealt with the agreement he signed. He wants the support of the courts to stand for re-election. Current rules forbid it. He is also challenging the union over whether it acted in line with its own rule-book.
Already in the throes of cash and membership crises, the decision to suspend Mr Akker and insist that he steps down - on the eve of the annual conference in Scarborough - has split the union.
One executive member said: "I wanted the man to go, but not this inept way. We are supposed to be a democratic union."
The Wirral branch is threatening to take a stand that would humiliate those responsible for handling the affair, if not the whole executive.
John Pennel, branch secretary, said branches he had contacted were shocked by "the speed of Akker's execution". Many would be demanding reinstatement, he said. The branch recently sent him a commemorative plaque for what they saw as brilliant handling of their dispute.
The branch is intent on having Mr Akker lead the delegation but, if not, Mr Pennel said in clear defiance of the executive, "any delegation to see David Blunkett and ministers will include John Akker".
Roger Ward, chief executive of the Association of Colleges, said: "It is typical NATFHE duplicity. They complain to Lord Nolan's Committee that employers are asking employees to sign confidentiality clauses while insisting the general secretary signs such a clause."