A Pounds 200,000 cut at Larkmead school in Abingdon has had dramatic effects: four fewer teachers, rising class sizes and loss of maths, science and design technology lessons for Years 7 and 8 pupils since the start of term.
"There was no real choice," said Rod Walker, headteacher.
"The governors consulted parents and teachers and it was judged that for the younger children it was better to give them fewer lessons but not to increase their class sizes.
"For our older children, we have had to increase class sizes. The most dramatic rise has been in Year 10 science where classes now have 24 pupils rather than 20."
But if the cuts are hitting hard this year at Larkmead, a 1,050-pupil school, next year the effects are likely to be even worse.
By the 1996-97 financial year the school, whose budget is Pounds 2 million this year, will have used up nearly all its Pounds 100,000 reserves.
Mr Walker, who chairs a group of Oxfordshire secondary headteachers, fears that other schools in the county will have to take similarly drastic steps to make ends meet.
"This is the thin end of the wedge. Next year schools will not have the option of whether to have large classes or reduce the length of the teaching week - I believe they will have to do a combination of both."
While many schools in Oxfordshire discussed the possibility of part-time education because of the county's Pounds 11.6 million budget cut this year, it is believed that Larkmead is the only secondary to have gone down that road.
Year 7 pupils have lost two out of 30 lessons each week - one maths and one science. Year 8 students lose a design technology session.
By reducing the teaching week for 12 and 13-year-olds to 23 hours for Year 7 pupils and 23 hours 45 minutes for Year 8, the school has managed to keep class sizes down to 23 and 24 pupils. The pupils leave school at 2.35pm instead of 3.20pm on Friday and the Year 7 pupils also lose another lesson during the week.
They are not set work to do outside school, apart from the normal homework.
And, said Mr Walker: "For older pupils you can't fit in the national curriculum at key stage 4 in the sort of time we were looking at so the option would be continued increase in class sizes at 30 and over."