As a new school year begins, school heads across the country will be trying to fill up teaching openings in their classrooms.
Some teachers do supply jobs to escape paperwork
It is more than likely that most of them will turn to temporary, "supply" teachers at some point in the months ahead.
But one who will not be using them anytime soon is Sylvia Moore.
The head of Watford's Francis Combe School could not believe her eyes when some of her pupils set part of a classroom on fire, while the supply teacher who was supposed to be looking after them was busy talking on his mobile phone outside.
Another supply teacher spent the whole term knitting instead of teaching.
"We had to do something because learning was being hampered," said Ms Moore.
"When we have new supply teachers, we normally spend some time training them on behaviour management, how to cover lessons, and we give them loads of guidance.
"We did a lot to make their jobs easier but many of these supply teachers do not have the commitment to the profession.
"Children are children. If they think they can get away with bad behaviour they will take advantage."
Ms Moore not only doubts the commitment of agency teachers but the training given to them by supply agencies before they are sent into classrooms.
"If you want to drive a car, you have to pass a driving test. It seems as if agencies are taking on people without assessing their skills, not minding whether these teachers can teach a subject or handle our children," she said.
Now, Ms Moore has trained her own team of paraprofessionals, who not only provide cover for absent teachers but also run the school's study centre and are the first port of call for parents.
In addition, Ms Moore believes the team of 24 were instrumental in the school's success at this year's GCSE-level exams.
The proportion of pupils who scored the equivalent of five or more A*-C grades more doubled from last year.
"The students can't misbehave, because if they do they know the paraprofessionals care enough to do something about it."
Ms Moore may not be the only head who is unsatisfied with the quality of services being provided by supply teachers.
Recent surveys have pointed to a growing disenchantment among school leaders.
A study by the National Association of Head Teachers (NAHT) suggests one in five London schools spent between £50,000 and £200,000 on employing agency staff. One even spent more than £500,000.
However, less than a third of the schools surveyed were confident that teachers provided by the agencies would have qualified teacher status and only 23% were confident that supply teachers would be familiar with the national curriculum.
There are some 14,750 supply teachers in schools on any given day. Around a third of these are provided by private teacher supply agencies.
The use of supply teachers may be an integral part of our education system but educationists say the rising number of them on long-term contracts is making it more difficult to find qualified people for short-term cover.
Supply teaching is also becoming a more popular choice for experienced teaching staff who are moving sectors to escape some of the burdens of a full-time, permanent role.
Head teachers are not the only people dissatisfied. Supply teachers themselves have their grievances against schools and the agencies they work for.
Being a supply teacher, they believe, can be a difficult and stressful job.
A former supply teacher who wants to remain anonymous said that for the most part, senior staff were keen to hold on to agency staff as long as they had classroom discipline and control.
But he said some difficulties arose from a lack of work being set or incorrect student lists.
"Sometimes you would be expected to follow a scant lesson plan in a curriculum area you were totally unfamiliar with.
"Supply agencies would often describe schools in various ways. The word 'challenging' was rarely used," he added.
However, recruitment agencies say they not only provide supply teachers with training before sending them into schools, but they also vet and monitor them as well.
Reed Education Professionals is one of the biggest players in the business.
Richard Taylor, a regional manager, said every supply teacher his agency handled went through introductory courses.
These were followed by a training need analysis of each teacher, which looked at every aspect of teaching and identified which course or courses would be of value.
"Continuing professional development courses are available to every teachers on our book," Mr Taylor said.
"There's also continuing monitoring and evaluation of a supply teacher which involved informal and formal discussions with head teachers, year heads and heads of department."
Mr Taylor wants head teachers to ensure that supply teachers and in-house staff all have access to the fullest information.
"Communication is the key," he said.
"Supply teachers should be introduced to permanent staff and be given information on a wide range of issues including reporting lines, school discipline policies and school hours."