Headteachers will be able to delegate responsibility for determining teachers' pay to other staff, but will not be required to do so, it was announced this week.
But the move is contentious with the National Association of Head Teachers threatening to sue the Government, alleging it is illegally undermining heads' authority and control in their schools.
And the biggest teachers' union, the National Union of Teachers, objects to teachers "having their pay and performance decided by their mate up the corridor".
The new performance management regulations, laid before parliament, have already been beset by NUT legal action. Their implementation has been delayed by 12 months and they will come into effect in September next year.
Ministers did offer a compromise: the draft regulations would have required delegation, but now it has been made optional.
Critics are forced to acknowledge that something must be done about headteachers' workloads. Secondary heads are now working 65.1 hours a week, up from 60.8 hours in 2000, according to a survey by the School Teachers'
Review Body issued this week.
Their deputies are now working 61 hours, and primary heads' workloads this year also increased slightly to 53.5 hours, bucking a previous downward trend.
The pressure and workload has had an impact on the health of many school leaders, according to a membership survey by one of the headteachers'
By contrast, the workload agreement between the Government, employers and some unions has helped classroom teachers get home at a more reasonable hour at night. Primary teachers are working 50.1 hours a week, and secondary teachers 49.1 hours, two hours less than in 2000.
Unions that are members of the social partnership with government and employers hailed teachers' decreasing hours as a vindication of their workload agreement.
Chris Keates, general secretary of the NASUWT, said teachers were benefiting from getting half a day planning and marking time and were no longer carrying out many administrative tasks.
John Dunford, general secretary of the Association of College and School Leaders, also welcomed the workload reduction for teachers, but blamed heads' increased workloads on a "deluge" of initiatives.
Which is why he believes it is appropriate to offload some of the work of reviewing teachers' performance onto line managers, such as heads of department, who are better placed to judge the performance of their colleagues.
Kerry George, head of pay and conditions at the National Association of Head Teachers, which is not part of the partnership, said headteachers were run off their feet, covering in classrooms to allow teachers their planning time and dealing with red tape like health and safety regulations.
"We've got local authorities asking heads to go round and test water supplies for legionella. That's not an appropriate responsibility for a head."
But at the same time, she said, the new performance management regulations were putting them in an invidious position by forcing them to either assess the pay and performance of all their teachers or delegate entirely, undermining their freedom and autonomy in their own schools.
The union was talking to its lawyers and considering legal action against the new regulations, she said.
The NAHT and the other unions did welcome many of the other changes in the regulations, such as the reduction in classroom observation of teachers except where there are performance issues.
THE VARIED WORKLOAD
Some staff working more, others less
2000 2003 2004 2005 2006
Headteachers 58.9 55.5 55.6 52.9 53.5
Deputy heads 56.2 56.4 55.7 55.7 53.4
Classroom teachers 52.8 51.8 52.5 50.9 50.1
Headteachers 60.8 60.9 60.8 62.6 65.1
Deputy head 58.6 56.5 54.1 58.1 61.0
Heads of facultydepartment 52.9 52.7 51.6 51.2 51.5
Classroom teachers 51.3 50.8 49.9 49.3 49.1
Figures from the Office of Manpower Economics