Speaking at the NASUWT conference, Ms Kelly was expected to give details of plans in the new education bill for local authorities to issue “improvement notices” to schools they believe are mismanaged.

Schools which fail to respond to the notices within a year will be failed by inspectors.

Ms Kelly was expected to say that the notices could be used to help teachers who suffer from bullying by their bosses or who do not receive their compulsory free periods for planning or marking.

Chris Keates, NASUWT general secretary, said teachers would appreciate the protection such notices could provide.

Her union is expected to back a motion on Saturday criticising heads who use self-evaluation forms and Ofsted inspections as an excuse to observe lessons excessively. “This practice is yet another example of management bullying and is unprofessional,” the motion states.

The National Union of Teachers is expected to press for a public campaign against workplace bullying at its conference.

Delegates are likely to back a motion which states that “the persistent criticism of performance, attendance or other personal factors serves to undermine a teacher’s confidence, self-esteem and health”.

Members of the Association of Teachers and Lecturers voted to reduce classroom observation earlier this week.

Kim Knappett, head of department in Forest Hill school in Lewisham, South London, said that time spent by senior staff observing lessons would be better spent teaching.

“What concerns me is not just the stress of observation but the amount my pupils miss out on because of the observations I do. This is not just the observation itself but pre-meetings, preparing and writing written feedback and time for verbal feedback to the teacher”, she said.

The Education Secretary was also expected to announce pound;30 million to help improve failing schools, which will be shared between 80 local authorities.