Class sizes

The union’s policy on class sizes sets out the following limits which, if exceeded, raise the possibility of the union seeking to enforce these limits through industrial action if the situation cannot be improved by negotiation:

• 26 pupils in the case of early years foundation stage classes with one teacher and a support staff member with minimum NVQ level 3 qualifications
• 27 pupils in the case of KS 1 classes
• 24 pupils in the case of mixed age classes
• 20 pupils in the case of practical classes (see below)
• 15 pupils in the case of classes of pupils needing particular small group or individual attention
• 30 in other cases.

DfE guidance

In general, DfE advice has tended to focus on the relationship between pupil numbers and available teaching space. 

Primary schools

In primary schools, the ‘standard’ classroom size for a class of 30 pupils is around 62m2 for reception and infant classrooms and 55m2 for junior classrooms (see Building Bulletin 103).  Such space limitations automatically place constraints on the amount of ‘free’ space available in the classroom, the types of work attempted and the ability of teachers and classroom assistants to engage and supervise effectively. For more complex design and technology, science, or art projects many schools make use of shared specialist practical areas which can be accessed as required by all classes on a rota basis. It is less likely, however, that such space will be available in older school buildings.

Secondary schools

For secondary schools, see again Building Bulletin 103 which gives area guidelines for different subjects depending on the activities taking place in them.  A number of these are summarised in the table below.

Recommended area (m²) according to group size :

Design and technology classrooms

It will be noted that some of the classrooms mentioned above indicate class sizes of above 20 for design and technology groups – higher than long standing convention and established practice would dictate. Indeed, British Standard 4163 on safety in design and technology in schools cites the maximum number of students in any one work area as 20 students with one competent, qualified teacher. The employer may choose to control the risk by another means, but it must control the risk. For example, the employer may decide to employ two competent and qualified teachers for one group in an area if the number exceeds 20.

Science laboratories

As far as science classrooms are concerned, the now out-of-print DfE publication Safety in Science Laboratories 1996 states: “There is no statutory limitation on class size in any subject in schools in England and Wales. Teachers who are concerned that risks in practical work are increased to an unacceptable level because of the class size should report their concerns to the head of their science department and, if necessary, their head teacher. It may be possible to adopt alternative methods for particular pieces of work. However, if risks cannot be made acceptable, the activity must cease until it can be resumed safely.” (para 7.6 page 25).

Building Bulletin 80, Science Accommodation in Secondary Schools, which is an archived publication and may not reflect current government policy or guidance, recommends a space range of 83 to 99m2 for a group of 30 KS3/4 pupils, adding that “the range of activities being undertaken, the level of storage kept in the laboratory, the number of pupils with special needs, and the type of furniture system used can all affect area requirements”.

It should also be borne in mind that some employers will have established their own rules about maximum class sizes for science lessons. Laboratories in Hertfordshire, for example, are designed to allow 2m² free floor space (excluding the area occupied by benches and cupboards etc) for pupils aged 11-16. This is considered to be the amount of space required for safe working. The authority also specifies that in laboratories with fixed benches each pupil needs approximately 700mm of bench space.

Physical education

Again, no statutory limit is placed on class sizes in PE lessons. In determining staff/pupil ratios, therefore, it is necessary to rely on health and safety legislation and in particular the risk assessment process (see below).

When determining the size of teaching groups in PE, account should be taken of:

• the nature of the activity
• the location of the activity e.g., indoor/outdoor
• the age, experience, maturity, competence, and behavioural/emotional characteristics of the pupils.

The school or local authority/trust has a responsibility to carry out ‘suitable and sufficient’ risk assessments in all curriculum areas, including PE. Where there is a gap in such provision, the school/local authority/trust is failing to comply with the law.

If there is a risk assessment, but in the professional opinion of PE staff/head of PE it is insufficient regarding its provisions on class sizes, the matter should be raised urgently with senior management in order that it might be properly reviewed.

Should such a review be unsatisfactory in the professional opinion of PE staff/head of PE, or should a request to undertake one be ignored, NEU members should contact the AdviceLine in England and Wales on 0345 811 8111 or in Northern Ireland contact 028 9078 2020.

Other practical subjects

The above table gives useful indications of minimum standards across a range of other practical subjects including music, drama, and art. In the view of the NEU, what matters is the nature of the activity and the circumstances in which it is being undertaken (see note on risk assessments above). Although some activities are inherently more hazardous than others, all practical activities can become hazardous in some circumstances due to factors such as age and ability of pupils, design of work areas, experience of staff etc.

Before/after school clubs

Children of mixed ages attend before and after school clubs and often take part in a range of exciting activities, with varying levels of risk. As with class sizes during the school day, thorough risk assessments on pupil numbers will determine the available space, equipment, furniture, activities, and pupil characteristics, and from thence the appropriate staffing levels and maximum pupil numbers.

Pupils with special educational needs – special schools and mainstream

Many pupils with SEN are at particular risk in practical activities and this is a key factor when considering group size. It is possible some students will require additional support for practical activities depending on the nature of their learning difficulty. Where the range of abilities in a class is very mixed or a high proportion of pupils have special needs, class sizes should be reduced.

Building Bulletin 103 states that “the recommended maximum net area may be needed where there are a very high proportion of pupils with SEN or disabilities” - in other words, the more pupils with SEND, the more space is required.

Meanwhile, Building Bulletin 104 gives details of space sizes in SEND and alternative provision schools.

General health and safety legislation

The Health and Safety at Work etc. Act 1974 places a general duty on the employer to ensure, as far as is reasonably practicable, the health, safety and welfare of its staff and pupils. This means that it is the employer’s responsibility to put such arrangements in place with regard to class size in practical lessons to ensure that the risk of harm is properly controlled, a process which should be done by means of a suitable risk assessment – as required by the Management of Health and Safety Regulations 1999.

A thorough risk assessment on class size in practical subjects will determine the available space, equipment, furniture, activities and pupil characteristics, and from thence the appropriate staffing levels and maximum pupil numbers. A risk assessment will entail a careful examination of hazards likely to exist, an assessment of whether the hazards are likely to harm anyone and what precautions need to be taken. Employers have specific legal duties to carry out risk assessments for all areas of workplace health and safety, and to appoint a ‘competent’ person or persons to carry them out.

If the rooms are so designed that, as the teacher circulates within the work area, a clear view cannot be obtained of all working situations, it will be necessary to reduce the size of classes. Supervision in work areas is complicated by the fact that the teacher will occasionally need to obtain materials or equipment from the store, where direct visual contact is highly likely to be impossible.

Inexperienced teachers need time and support to develop the demanding skills required for the successful delivery of practical lessons. A suitable ‘cap’ should be placed on pupil numbers in practical classes taken by less experienced teachers.

Decisions on class sizes might be influenced where appropriate support staff can be timetabled to assist during practical sessions, for example with some aspects of equipment use and the collection of materials from stores and elsewhere.

Further information

In addition to maximising the safety and wellbeing of pupils, there is a need to recognise the effect of class size on teacher stress and to consider at what point this becomes a health and safety issue – for both teacher and pupils. A significant factor affecting the mental and physical health of a teacher might be the mutually reinforcing effects of excessive stress and pupils’ frustration caused by a lack of individual attention in over-large classes. Teachers are aware of the potential areas of danger in the classroom, and stress can be caused by continually trying to identify and anticipate problems.

It should also be recognised that some equipment in design and technology areas can generate significant noise, thereby causing physical stress when teachers are obliged to talk above the noise. Checks should be undertaken to determine if the regulations governing noise at work are being complied with. If maximum exposure levels are exceeded, remedial action must be taken – the simplest and most effective being class size reduction. Teachers should also be vigilant for signs of vocal strain in this context.

Teachers should be aware that under Section 7 of the Health and Safety at Work etc Act 1974, employees are required to take reasonable care for the health and safety of themselves and others who may be affected by their acts or omissions at work. This means that teachers can legitimately refuse to participate in activities which risk their own health and safety and/or that of their pupils. Advice should, however, always be sought from the NEU before doing so.