The unions claim that teachers' jobs will be more vulnerable when the proposed changes to employment regulations remove the requirement of employers who make fewer than 20 redundancies over 90 days to consult with unions. The law, which the Department of Employment intends to have in place by the end of this month, will eventually affect all schools in the United Kingdom.
The proposed change came about after the European Court took the UK to task for failing to comply with two employment directives. Michael Portillo's response has been to use another part of the 1975 Collective Redundancies Directive, which includes the threshold of 20, to undermine union power.
Brian Clegg, assistant secretary (salaries) of the National Association of Schoolmasters Union of Women Teachers, said: "This could be an own-goal for Mr Portillo. The system now requires employers to warn of possible redundancies by issuing Section 188 notices. This gives both sides time to consult and work out deals.
"If schools are intent on freezing out unions, we may be forced to call industrial action as a first resort when we get wind of redundancies, to force consultation rather than waiting until all avenues have been explored."
Union officials, many currently fighting redundancies, fear the legislation will make it easier for heads and governing bodies to target certain teachers. The Association of Teachers and Lecturers estimate that intervention by the unions has "saved" almost 1,500 jobs this year.
Ted Hargreaves, an NASUWT national executive member from Shropshire, said: "We have already had a tussle with some governing bodies over consultation and are very concerned about the selection procedures used by some of them. I think the legislation will increase the misapplication of redundancies."
Unions will still be able to take up the case of individual members facing redundancy, but only when they are brought in by the teacher.
David Hart, general secretary of the National Association of Head Teachers, said while the regulations meant a huge change of procedure on paper, in practice he "would not expect any self-respecting head or governing body to exclude unions from the process".