Teachers will be lobbying the leader of Nottingham City Council today over its controversial plans to change term-times in the city.
Members of the UK's largest teaching union, the NASUWT, are planning to demonstrate outside the council offices this evening.
The council wants to switch to a five-term year with a shorter summer holiday. It claims the changes would boost pupils' learning and attendance.
But the union says the new-look academic year would be chaotic and disruptive for teachers, parents and pupils.
It claims there is no proven educational benefit to a five-term year, and the eight-week terms created would be too long.
It would also leave children in city schools with siblings in county schools on different holiday patterns.
The NASUWT held an indicative ballot in which 80% of its members voted in favour of industrial action over the issue.
The National Union of Teachers has already held three one-day strikes, but suspended any further action while talks continue.