NUT calls for strike action may derail a planned merger to create a "super" teaching union with over 400,000 members.

Executive members of the NASUWT are split on the proposed merger and many at the union's conference are hostile to the perceived militancy of the NUT, described as "a bunch of bearded 1980s throwbacks" by one delegate.

However, the unions have united over planned industrial action in pursuit of a 35-hour working week for teachers.