Brecon High School in special measures after inspection
A Powys high school has been placed in special measures following a poor inspection.
Powys council said the report by Welsh schools' inspection body Estyn into Brecon High School was "very disappointing".
A team of school improvement officers from Powys and Ceredigion councils will support the secondary school.
An action plan is being drawn up to address the problems.
Inspectors will now visit Brecon High School every term to monitor progress.
A monitoring visit carried out by Estyn in February judged that the school had not made enough progress addressing recommendations following an inspection in 2012.
It has downgraded it from "in need of significant improvement" to "in need of special measures".
Powys Council's Cabinet Member for Education and Children's Services, Myfanwy Alexander said: "The report is very disappointing and a matter of great concern for the school, the governing body and the council.
"The report and recommendations, which have been accepted by the head teacher, staff and governing body, is very fair and will form the basis of a detailed action plan to address key areas requiring improvement.
"The council and school improvement colleagues from Ceredigion will work with the school and its governing body to identify reasons for the inspection outcome and to make sure we deliver significant and rapid improvements."
Chair of the school's governors David Meredith said the school accepted that overall, progress had been too slow.
He added: "The school has had a difficult history in recent years and I am confident that this is now firmly behind us."
Brecon High School is the second high school in Powys to be placed in special measures.
John Beddoes School in Presteigne was put in that category in December 2012.
Last December Education Minister Huw Lewis gave the go-ahead to shut the school in April when it will become a campus of Newtown High School.
Earlier this year a plan to open a £75m campus replacing Brecon High school, a further education college and leisure centre in the town was put back a year.
The campus is now expected to open in September 2018.