An ITV News investigation has revealed that more than 800 teachers and school support staff are being made redundant around Wales.
Exclusive figures, obtained via Freedom of Information requests, also show a further 100 school posts at risk of redundancy.
Teaching unions say the "unprecedented level of job loss" is due to budget cuts and under-funding of schools here, and will inevitably have an impact on pupils and standards of learning.
The Welsh Government insists it has met its commitment to protect school funding from the degree of cuts passed down from Westminster.
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The amount of money spent per pupil in Wales has fallen this year for the first time in a decade.
For 2015-16, it is £5,526, a decrease from last year of 1.1 per cent, or £64 per pupil.
Overall, school funding is £2.496bn, 1 per cent down on last year.
THE SCALE OF THE REDUNDANCIES
Many schools say that a reduction in funding this year, after several years of significant budget pressures, meant they have had to look for redundancies, as staff make up the majority of their costs.
20 of Wales' 22 local authorities have provided figures on teacher and support staff redundancies, in response to our Freedom of Information requests.
Support staff range from teaching assistants to caretakers, secretaries and technicians.
Wales total (full-time equivalent posts):
Agreed redundancies - 808
Additional redundancies earmarked - 99
Agreed teachers redundancies - 364
Agreed support staff redundancies - 444
A small majority of the redundancies are voluntary, meaning just under half are compulsory. It is difficult to be any more precise, due to local authorities providing the figures in different forms.
There are around 25,000 teachers and 25,000 support staff in state schools in Wales, according to 2014 figures. The redundancies therefore make up between 1.5 per cent and 2 per cent of the school workforce.
Find out how your local area is affected...
Redundancies for 2015-16 (full-time equivalent posts):
Anglesey - 4 agreed (3 teachers, 1 support staff), 8 additional earmarked
Blaenau Gwent - 12 agreed (7 teachers, 5 support staff), 1 additional earmarked
Bridgend - figures not provided
Caerphilly - 4 agreed (2 teachers, 2 support staff), 5 additional earmarked
Cardiff - figures not yet provided
Carmarthenshire - 59 agreed (36 teachers, 23 support staff), 3 additional earmarked
Ceredigion - 46 agreed (27 teachers, 19 support staff)
Conwy - 7 agreed (7 support staff)
Denbighshire - 6 agreed (3 teachers, 3 support staff), 16 additional earmarked
Flintshire - 32 agreed (16 teachers, 16 support staff)
Gwynedd - 47 agreed (25 teachers, 22 support staff)
Merthyr Tydfil - 50 earmarked (10 teachers, 40 support staff)
Monmouthshire - 37 agreed (13 teachers, 24 support staff)
Neath Port Talbot - 83 agreed (29 teachers, 54 support staff), 16 additional earmarked
Newport - 5 agreed (5 teachers)
Pembrokeshire - 35 agreed (18 teachers, 17 support staff)
Powys - 65 agreed (29 teachers, 36 additional support staff)
Rhondda Cynon Taf - 142 agreed (60 teachers, 82 support staff)
Swansea - 117 agreed (51 teachers, 66 support staff)
Torfaen - 44 agreed (11 teachers, 33 support staff)
Vale of Glamorgan - 25 agreed (11 teachers, 14 support staff)
Wrexham - 38 agreed (18 teachers, 20 support staff)
IMPACT ON LEARNING
Many of the redundancies will have been identified after the start of the financial year in April and, often, after notice periods that include the summer holidays, will mean staff finish school this week, and don't return in September.
A significant number of individual staff will have been redeployed, or found work elsewhere, with their posts in school being made redundant.
Schools and teaching unions here say the cuts to staffing levels will have a major impact on pupils and their learning.
Dr Philip Dixon, Director of the Association of Teachers and Lecturers Cymru, told us he was "horrified" to see the scale of redundancies.
There will be fewer teachers in their schools; there will be fewer learning assistants in their schools, that will mean bigger class sizes, it will mean less professional expertise. The quality of education is going to suffer because of that.
Rex Phillips, NASUWT National Official for Wales, said "it is unrealistic to expect the year-on-year improvement in standards in Welsh schools to be maintained against an ever decreasing school workforce."
The information that has been revealed through the ITV News Freedom of Information requests has confirmed our view that there has been an unprecedented level of job loss in schools across Wales this year.
The Welsh Government says it is "extremely proud that through the tough times the Welsh Government has been there to shelter schools from the worst of the cuts" imposed by Westminster.
Workforce planning and staffing are both matters for local authorities and are not issues on which the Welsh Government can intervene. However it is important to recognise that workforce changes can be driven by a range of factors including school reorganisation, fluctuating pupil numbers, funding and changing priorities at a local, regional or national level.