Principals have demanded that Westminster MPs address "unacceptable" cuts to education funding in Northern Ireland.
Representatives from the National Association of Head Teachers (NAHT) attended a briefing for MPs last night in the House of Commons, setting out the reality that cuts were having on children.
NAHT president Paul McClenaghan said: "Despite rising pupil numbers in primary and nursery schools in recent years, school budgets have not received investment reflective of this increasing demand."
He explained the budget reductions meant a cut of £61 per pupil in primary schools, £83 in nursery schools for full-time pupils, and £25 per pupil at post-primary level.
"In real terms, what these budget reductions equate to will be staff cuts, larger class sizes, cutbacks in support for children with additional needs, thus resulting in further pressure on parents to subsidise resources," he added.
"Essential school maintenance and refurbishment of buildings to meet the growing demand of the school population will be impossible."
Calling the situation "unacceptable", he repeated his demands for schools to be properly resourced.
Earlier this week SDLP MLA Daniel McCrossan claimed education in Northern Ireland was facing an additional "black hole" of £100m due to the Stormont deadlock.
He made the comments after receiving a letter from the civil servant now managing the education budget here.
Permanent secretary Derek Baker wrote that the department had £24m less to work with in 2017-18 than the previous year.
"In addition, it faces unavoidable, rising cost pressures in such areas as teaching and non-teaching staff pay, special educational needs and essential school maintenance. Together these factors create cost pressures of over £100m to be addressed," he said.
"This has unfortunately resulted in the need for difficult decisions to cease or reduce a number of programmes... put simply, I cannot spend money the department does not have."