His speech looked set to be as brutally received as Patricia Hewitt's in 2006, when she was forced to abandon her address to the Royal College of Nurses conference.
But the trade union leaders who made the high-risk decision to invite Vince Cable to their annual conference have suddenly got cold feet and cancelled the invitation.
Had the Business Secretary spoken at the TUC annual conference in Manchester it would have been the first time union delegates had listened there to any Cabinet minister other than a Labour one. The only Liberal Democrat ever to address the conference was Charles Kennedy, in 2002.
The idea of inviting Mr Cable as guest speaker was part of a drive by the TUC's pragmatic General Secretary, Brendan Barber, to deal with the coalition government through negotiation rather than confrontation.
But leaders of individual unions objected, and there was speculation that left-wing delegates would walk out or stage demonstrations.
Mr Barber had originally planned to have David Cameron on stage as the first Tory Prime Minister in history to address the TUC. But he turned down the invitation as it coincided with his planned paternity leave for his fourth child, who is due to be born in September.
The idea was denounced as a "Grade A mistake" by the railway union leader, Bob Crow, who wants the unions to work out a campaign against the Government's planned cuts in public services "rather than having a lecture on fiscal fascism forced down our throats".
But TUC leaders insisted yesterday that Mr Barber and his deputy, Frances O'Grady, will meet Mr Cable privately in the autumn. Mr Cable's office said he was "relaxed" about the withdrawal of the invitation to speak at the conference.Reuse content