School self-evaluation, the replacement of management allowances with a new staffing structure and the pressure on timetables caused by guaranteed non-contact time for teachers have left heads unable to take the dedicated headship time promised in the workforce agreement.
One head complained: "I have only been able to provide PPA using qualified teachers by not having any PPA myself."
The anonymous survey of 40 primary heads and deputies who attended the NUT's leadership convention found more than a third had been unable to fully implement leadership and management time as set out in the agreement.
Eight out of 10 reported an increase in workload compared to last year.
Seven out of 10 reported the requirement to complete and up-date Ofsted's self-evaluation form has also had a significant effect on their workload.
Despite this, there was broad support for the new lighter-touch inspection arrangements introduced last month.