Stephen Dorrell, the Tories' education spokesman, said members of the Cabinet were lining up to oppose the Prime Minister by taking the trade unions' side.
Gordon Brown, the Chancellor, had firmly positioned himself in the Trades Union Congress camp when he recently addressed a meeting of the Transport & General Workers' Union, Mr Dorrell said. "The Chancellor let slip that he was on their side. That's where the Chancellor is. He is busy building his position."
He added that John Prescott, the Deputy Prime Minister;David Blunkett, the Secretary of State for Education and Employment; Chris Smith, the Secretary of State for Culture, Media and Sport; Frank Dobson, the Secretary of State for Health; and Ron Davies, the Secretary of State for Wales, were all privately behind the unions.
While Tony Blair was taking the Confederation of British Industry's view that a majority of eligible employees should have to vote in favour of recognition, the other ministers were taking the TUC line that it should be a majority of those who voted.
Mr Dorrell likened the dispute to the split over Barbara Castle's 1969 In Place of Strife proposals on the unions, which were abandoned after a row within the party.
"Is this to be the history of In Place of Strife, volume two? The reality is that this is not just a matter of principle. Trade union bosses understand very clearly that this is a matter of straight power politics," he said.
The Minister of State for Trade and Industry, Ian McCartney, said the CBI and the TUC were to be congratulated in having resolved many of their differences on the issue. The final outcome would be announced in the Fairness at Work White Paper.
"I don't intend to negotiate with [Mr Dorrell,] someone who is totally opposed to having recognition in the workplace," Mr McCartney said.
"This government is the first in 18 years that has opened up any consultation and dialogue on representation in the workplace."