The threat, agreed at the National Union of Teachers' annual conference yesterday, comes as the academies programme is becoming increasingly linked to the "cash for peerages" row.
Delegates to the conference in Torquay voted overwhelmingly in favour of urging the union's executive to consider a national strike to block legislation that would pave the way for the new trust schools. They also warned of individual strikes if local schools opted for trust status or to become an academy. The union will also mount a national lobby of Parliament in a bid to persuade more MPs to oppose the legislation. Martin Reed, the executive member for North Yorkshire, told the conference: "Many in the Government thought we would not fight - big mistake, Mrs Kelly, we will."
Delegates warned that Mr Blair's plans would sound the death knell for comprehensive education. Richard Rieser, from Hackney, east London, said: "This is the biggest threat the union has faced since its inception because ths Bill seeks to destroy the state education system."
Under the Bill, all schools will be allowed to seek trust status - and go into partnership with private companies or faith groups who will then have the power to control the governing body and determine the curriculum. They will also have more freedom over their admissions policies - although rebel Labour MPs have won a concession from ministers that there will be no more selection. Academies, of which the Government intends to establish 200 by 2010, will be run in a similar fashion. Sponsors have to provide £2m to take over an academy. Ministers insist the programme is necessary to improve standards in schools.
However, Liam Conway, an NUT delegate from Central Nottinghamshire, argued: "The Bill is the academies' programme writ large. We should be taking pre-emptive action to stop it."
Yesterday's vote coincides with the "cash for peerages" row in which a government adviser and headteacher, Des Smith, was arrested after telling an undercover journalist that a sponsor could expect an honour if he or she sponsored five academies.
Jane Bassett, also from Hackney, told the conference: "We're facing a Government that's not strong - we're facing a Government that's in tatters and a Government that's prepared to sell peerages for academy sponsors."
Hazel Danson, from Kirklees, said Mr Blair's mantra of "education, education, education" had become "money, money, money".
The union's vote prompted an angry reaction from the Government last night. A spokesman said: "Strikes achieve only one thing - disruption to pupils' learning. This is a retrograde step based on arguments that don't stack up. The NUT has opposed many significant education reforms which have subsequently brought about the highest ever standards in schools. There is nothing to fear in this Bill and everything to be gained."