A GCSE physics class at an secondary school in the Isle of Man has no fewer than 56 students because of a shortage in qualified science teachers.
Castle Rushen High School has been forced to combine two Year 11 classes of 28 students since the beginning of the spring term.
It highlights a wider problem of Manx schools finding it difficult to recruit specialist teaching staff.
The Department of Education and Children accepted the situation is not ideal but said it would be unacceptable to deny the pupils the right to sit their physics GCSEs exams this summer.
It said CRHS has recently recruited two trainee science teachers.
In a statement, the DEC told iomtoday: ‘Castle Rushen High School has advertised for a physics teacher but it is a subject in which there is a British Isles-wide shortage of qualified teachers.
‘Two science teachers have recently departed for new posts and another science teacher is on maternity leave.
‘Therefore, as suitable science teaching resources are scarce, two Year 11 GCSE physics classes of 28 have been combined since the start on the spring term 2016.
‘As the students chose physics as a GCSE option and have undertaken more than a year of study, it was not acceptable to deny them the right to sit their exam this summer.
‘While the class has in it more students than would usually be desirable, and therefore is delivered ‘lecture style’, it is led by the subject leader for science, the school’s most senior/experienced science teacher, and he is supported in class by another staff member.
‘While students may not benefit from as much one to one time as might be ideal, the class is academically able and learning is available outside the classroom, too, in the form of a weekly lunchtime session, one to ones where requested and online resources.’
The DEC said a letter had been sent to parents explaining the situation and that ‘good dialogue’ has taken place.
It added: ‘As outlined only this week by Tony Draper, the president of the National Association of Headteachers, the island’s education system has much to commend it.
‘The DEC and its schools are capitalising on the strong points of the Manx system in developing initiatives to attract existing teachers to the island and trainee teachers into education.
‘Through these initiatives, Castle Rushen has recently recruited two very able trainee science teachers. The DEC and schools will continue to develop innovative ideas to ensure the island is an attractive option for teachers in order to deliver the best education to students.’
A report from the Organisation for Economic Co-operation and Development in 2014 found that the UK state sector had an average of 26, which was much higher than most countries in Europe.
The National Union of Teachers recommends a maximum class size of 18 in practical groups, including GCSE and other classes which involve teacher assessment of pupils.