Parents march over school funding in Shrewsbury
About 250 people have taken part in a march and rally calling for better funding for Shropshire schools.
Campaigners claim spending on education in the county would fall by £13.4m a year under government proposals and schools were facing a "funding crisis".
Elizabeth Dakin, a head teacher in Wem, said "vital services" were already being cut and education was affected.
The Department for Education said the plans were under consultation but would see funding in Shropshire rise by 0.1%.
Parents, teachers and pupils marched through Shrewsbury to a rally at The Quarry. The event was backed by several unions including the National Union of Teachers (NUT) and National Association of Head Teachers (NAHT).
Ms Dakin, head of Thomas Adams School, said education in the county was "already under-funded".
"We actually have nowhere else to cut," she said.
And Jean Evanson, divisional secretary of the NUT in Shropshire, said the proposals would mean larger class sizes and fewer staff to help children with special educational needs.
She added "all sorts of other repercussions" would include reductions in sport, music and other enrichment activities.
The Department for Education said the schools budget had been protected since 2010 and funding was at its highest in 2016-17.
But it added the "unfair, opaque and outdated" system for distributing funding was being changed. A consultation over its proposed national schools funding formula takes place until 22 March.
The proposals would mean "a cash boost" for more than half of schools in England, a spokesman said.
"We are consulting on the factors that will make up the formula and we know that it is important that we get this right so that every pound of the investment we make in education has the greatest impact," he said.