How many hours do teachers in England work?
Teachers' unions have warned about excessive workloads and complained about staff being put under too much pressure. The long working week has been one of the grievances prompting teachers to go on strike.
But are these claims justified? Teaching is unusual in that there is an official record of the number of hours worked in term time. The Department for Education runs an annual survey, where a sample of teachers in different types of school keep a diary of their working lives.
The last results, published in February, show the hours worked in 2013.
So how long is the working week?
For secondary head teachers, it stretches to an average of 63.3 hours per week - the longest of any of the teaching jobs. Primary classroom teachers worked longer hours - 59.3 hours - than their secondary school counterparts, who worked for 55.7 hours per week. The hours in a secondary academy were slightly less, at 55.2 hours.
How much of this is in the classroom?
Teaching hours are a minority of a teachers' workload, according to this survey. A primary school teacher will spend on average 19 hours a week of timetabled teaching. It's similar for secondary school classroom teachers, averaging 19.6 hours.
Secondary school head teachers have much lower levels of classroom time, at 2.8 hours per week.
Outside of this there will be time spent in school for lesson preparation, marking, supervising children away from the class and carrying out any other administration.
How much of the work is at home?
There is no quicker way to get into an argument with a teacher than to say how good it must be to finish work at 3.30pm every day.
The workload survey confirms that teachers are putting in a lot of hours outside of the school day, before 8am, after 6pm and at weekends.
For primary classroom teachers, 23.8% of their hours are worked out of school each week, with secondary head teachers working 21.5% and secondary classroom teachers 21.4%.
Primary heads put in more than six hours work every weekend, according to this work diary.
Too much paperwork and red tape?
Classroom primary teachers spend an average of 4.3 hours each week on general administration.
Not all of it is useful, the survey suggests. There are 45% of classroom teachers who think the amount of time spent on "unnecessary or bureaucratic" tasks has increased, with only 5% saying it has reduced.
The biggest cause of unnecessary paperwork, the teachers reported, was preparing for an Ofsted inspection. Head teachers also identified changing government policies and guidelines as generating "unnecessary" bureaucracy.
What about the holidays?
These working hours are based on weeks during the school term. It does not include the school holidays - which can be 13 or more weeks each year - which might lower the annual average of working hours. Although there are arguments from teachers that their work can spill into half terms and holidays, but this remains outside the remit of the work diary.