Primary heads who go on management courses are always being told to delegate. Consultants - and sometimes teachers from other sectors - are often surprised by the number of things a primary head has to do, from interviewing parents to dealing with minor disciplinary matters and carrying out running repairs in the computer room.
But in many cases the head is the only member of staff who has no full-time class responsibility. He or she is the only person who has the time to make that long phone call to the educational psychologist that perhaps would be better made by a special needs co-ordinator.
This is not new. Medium-sized primaries have traditionally been staffed on the basis of one teacher per class, in addition to the head. And in small schools the head has to take at least a share of a class.
consequently, primary teachers have become used to doing all their marking and preparation at home, making the occasional plea to government and local authorities for at least a small entitlement to "free" or "marking" time.
Recently, though, the pressure for more non-contact time has increased. Not only do teachers have a lot more paperwork, but the drive for standards means that those with management or subject responsibility are expected to monitor the work of their colleagues; Ofsted teams question subject leaders about how they monitor standards.
Some of this can be done away from the classroom - through planning meetings, looking at work, talking to teachers out of class. But there's no substitute for classroom observation. To achieve this, deputy heads and subject leaders must be freed from their own classes.
To some extent, this is a matter of budget priorities. A head who is determined to give his or her deputy some non-contact time can achieve it, albeit at the expense of other areas.
At Greenfield primary in Stourbridge, part of Dudley authority, head Anita Wheeler regards non-contact time for the deputy as a priority. So, although this is only a medium-sized primary with 280 pupils, Anita Wheeler's deputy, David Baker, does not have his own class, and teaches for only 60 per cent of the time. In his non-contact time, he works on planning and monitoring the curriculum and has a regular strategic planning afternoon with Mrs Wheeler. He is also, in her words, "highly visible for parents in the mornings".
She secured the governors' agreement for this arrangement when they appointed Mr Baker four years ago. She argued that their determination to raise standards meant that she had to have an effective deputy with time to do the job. "In appointing a deputy, I'm looking for someone who is going to be a head. They must have time for leadership," she says.
"If it's your priority, then you'll search the budget to make it happen. And if when you've allocated those funds you have financial problems, then you'll look for other ways of solving them."
The consequence for David Baker is that he feels able to live up to his job title. "If I didn't have the time, I wouldn't be a functioning deputy," he says. "I'd be a teacher who happens to be the deputy. And there's a difference."
Where the deputy is a full-time class teacher, he says, there can also be problems for his or her pupils. "The deputy can be called out of clas, and this is unfair both to the deputy and the children."
The governors have also supported Mrs Wheeler in finding small, but important, amounts of non-contact time for other teachers. She says: "In a school of this size, everyone is a subject leader. Everybody is involved in school improvement planning."
What this means is that every teacher bids for resources for his or subject, and this includes some non-contact time. "If someone wants to do a full audit of existing resources they might bid for a day or half-day to do it in. It means that different people are asking for different amounts at different times."
These are small packages of time, however - perhaps three days in a full year - for a subject leader. Anita Wheeler would love to be able to give more time for classroom observation. Standards have risen in leaps and bounds at Greenfield, but she feels that her team could do even better were they able to work with each other in class.
"Science is our focus at the moment," she says. "The subject leader has done a fantastic job. She's gone to the authority for funding, worked with the adviser on resources, bought in books, run staff meetings and completely organised the implementation of the Qualifications and Curriculum Authority scheme."
From that point, though, the subject is largely in the hands of the classroom teachers. What would really make the difference, says Mrs Wheeler, would be time for the subject leader to see her work put into practice.
"We need to be able to let her go into class with the teachers, to say, 'Let's do it together'. That would really consolidate it. If the Government really wants us to raise standards it needs to give schools the flexibility and funding to allow this to happen."
What, though, of time for a quiet session in a corner of the staffroom, doing marking or preparation? That seems to have become an even more remote possibility, as the emphasis has shifted to monitoring and team planning. David Baker has four non-contact afternoons a week but he doesn't use any of them for marking. Like all the other teachers, he does his marking and preparation at home.
The only thing that would change this would be a political decision to make non-contact time a conditions of service entitlement. Phil Willis, education spokesman for the Liberal Democrats, agrees. In his view, time and working conditions are at the top of teachers' agendas.
"It's not pay that's the bugbear," he says, "it's the bureaucracy. They say they've not time to do the job. That's why we have a policy which would give a mandatory right for time off for preparation for all primary teachers. It's going to be a fundamental commitment from us in the general election campaign. An hour a week would make a huge difference."
Lurking in the background, though, is a feeling that there's a limit to the number of times you can take a teacher away from children - especially younger ones - without hurting their education. There are also questions of availability and training of supply teachers, and about the status and role of the classroom assistant.
One way to achieve continuity when the teacher is away would be to enhance the training and role of the classroom assistant. The Lib Dems certainly believe so: they argue that every class should have its own assistant. Over to you, Mr Blunkett.