Anger over growing class sizes, underfunding and school inspections is reflected in the preliminary agenda for the National Union of Teachers' Easter conference.
And the militant approach taken by many motions voted by members on to the agenda ring a warning bell that the union is in no mood to soften its stance to suit any incoming Labour government.
Leading figures from the union's moderate and left-wing factions - which maintain a delicate balance on the NUT's national executive, warn that they expect more sympathetic treatment if Labour is victorious. But both sides are sceptical about the Labour leadership's current publicly-stated policies.
The conference agenda - which may be altered by amendments from branches or the national executive - has been drawn up as industrial action over class size flared at Ferney Lee infants and junior school in Todmorden, West Yorkshire. NUT members have started working to rule after 18 months of trying to resolve the dispute over a reception class of 39 children and several other classes with more than 30 pupils. At least 30 pupils are being sent home every day as a result.
The union accuses the headteacher, Sue Ellis, and the local authority, Calderdale, of refusing to negotiate, but hopes that talks planned for this week will resolve the dispute.
A left-wing motion on the NUT agenda from the Leicester and Hackney branches, which won the highest number of votes in the prioritisation process, calls for contracts for all teachers including limits on class sizes and a minimum of 20 per cent non-contact time.
Another motion from Croydon and Tameside calls for legislation to limit class sizes to 30 for all age groups and for a campaign on the issue with other organisations including the Fight Against Cuts in Education.
Other motions include calls for the abolition of the nursery vouchers scheme, the dismantling of the Office for Standards in Education and the sacking of its chief executive Chris Woodhead, and demands for the abolition of league tables by an incoming government.
The conference will also face a call for the union to campaign for a completely comprehensive education system "irrespective of the government in power".
Mostyn Phillips, executive member for Wales and chair of the union's key education and equal opportunities committee, said: "We will be pursuing our policies irrespective of any government policy.
"Whatever Labour is preaching now, it is also committed to consultation with the teacher unions. We hope that through genuine consultation we can persuade the Labour government of the wisdom of our policies. If we can't, we will be as opposed to a Labour government as we have been to the Conservatives."
Left-wing executive member for West Yorkshire Ian Murch, a founder member of the militant Campaign for a Democratic Fighting Union, identified testing, league tables, selection and funding as the areas most likely to trigger conflict with a new Labour government.
"It's not that the union has become more militant, but that the Labour party has shifted its ground," he said. "Four or five years ago, Labour's policies were broadly in line with the NUT's.
"But the fact that the motion on conditions of service has come top in the vote among branches shows that the pressure of work is becoming intolerable. "
The conference, to be held in Harrogate, will also face a call for the NUT to break with recent policy which has seen it forming a joint claim with other unions for an unspecified pay rise.
A motion from the NUT's Hackney and East London branches, voted top in the salaries and superannuation section of the agenda, calls for rises of 8 per cent plus Pounds 1,500 for all teachers, to be fully funded by the Government.