A “significant funding dip” is forcing schools to increase sixth form class sizes, with one school reporting 38 pupils in one class, according to the Grammar School Heads Association.
Jim Skinner, the association’s chief executive said: “We are facing a situation where high quality A-level provision will become the preserve of the independent sector.”
Three quarters (74 per cent) of the 76 grammar schools responding to a survey by the association said maximum class sizes had increased. The largest class size was 38 pupils and the average size of the largest group is 25.
Mr Skinner told Schools Week: “There is a significant funding dip for 16-19 education, with much lower funding than key stage 4 which precedes it, and the higher education which it leads onto.”
As a result, he said “schools and colleges have no choice other than to significantly increase class sizes and reduce the range of courses offered, with subjects such as modern foreign languages and music being lost at A-level”.
The Association of School and College Leaders (ASCL), which represents leaders at all forms of schools, said baseline funding for 16-19 year olds was inadequate and the survey findings reflected the picture across the whole of the post-16 state education sector.
Interim general secretary Malcolm Trobe said teachers’ workload was certain to increase as a result of bigger classes and there was a risk to student outcomes. “Teacher workload is bound to go up when working with A-level students, who are extremely keen to get a lot of written feedback.
“The danger quite clearly is that if you increase class size and reduce contact time you are potentially going to put at risk the grades and attainment that students are able to achieve.”
Devonport High School for Boys in Plymouth was one of the grammar schools responding to the survey. Deputy headteacher Dave Adams said he saw “an impact on teacher workload in terms of providing support to a larger group”.
He added: “The government says it wants to tackle increased teacher workload – but at the same time the funding situation for sixth forms is making class sizes larger.”
The school has experienced a 20 per cent cut in funding to the sixth form during the last five years, Mr Adams said.
He added: “We need 15-20 students in a class to make it economically viable. What we are seeing now is economics and maths groups going up to 26 and 27 students.”
James Kewin, the deputy chief executive of the Sixth Form Colleges’ Association agreed increasing class size was “one of the many strategies sixth form colleges are adopting to deal with falling funding and increased costs”.
A Department for Education spokesperson said: “We recognise the importance of investing in education – which is why, thanks to the difficult decisions we have taken elsewhere, we have been able to protect core 16 to 19 funding.
“As part of this, we have provided sufficient funds for every full-time student to do a full timetable of courses regardless of institution and increased support for those who successfully study four or more A-levels and large TechBacc programmes.
“At the same time we have ended the unfair difference between post-16 schools and colleges by funding them per student to ensure that all young people leave education with the skills they need to thrive in modern Britain.”