A poll for The TES shows those most likely to back merger are men and members of the National Union of Teachers, the biggest and most militant of the three TUC-affiliated unions. Secondary and primary teachers from all parts of the country supported the move, the poll of 1,000 teachers by FDS International shows.

Members of the traditionally more moderate Association of Teachers and Lecturers are least enthusiastic (see chart, right, and box, far left) but even so, a narrow majority favour merger.

The poll shows that the NUT is the leading union for primary staff while the NASUWT has slightly more members in secondaries. The NUT is particularly strong in London and the South-east and the poll confirms its traditional image as the most likely to appeal to younger teachers and women.

It suggests younger staff may be less committed to unions: 8 per cent of those in the job for less than five years are non-members. Some older teachers, particularly in primaries, were also members of unions such as the National Association of Head Teachers even though they had spent most of their time in the classroom.

The poll is based on phone interviews conducted with classroom teachers in state schools in England between March 11 and 20. The sample was evenly divided between primary and secondary staff. No more than two interviews were obtained per school.

Clare Dean