Liberal Democrat MPs and delegates have voted to campaign against the coalition's policies relating to free schools and academies.
Christine Blower, general secretary of the National Union of Teachers (NUT), said this has shown up a clear conflict between the two parties.
"Academies and free schools are Tory policies and stand in direct opposition to previous Liberal Democrat thinking," she commented.
Ms Blower noted that before the general election, MP Sarah Teather had branded the free schools initiative as a shambles.
"The grass roots of the party overwhelming spoke of their rejection of academies and free schools. They know, as does the NUT, that implementation of this policy will lead to a fragmentation of the education system which will benefit the wealthy and leave the most disadvantaged behind," she explained.
These are decisive policies and the delegates at this week's conference have overwhelmingly indicated that they are not wanted, Ms Blower added.