Tasker Milward school's performance prompts Estyn action
A Pembrokeshire secondary has been put in special measures after failing to improve enough in the past year.
Inspectors decided to take action at Tasker Milward Voluntary Controlled School in Haverfordwest after raising concerns on a visit last month.
Last year, education inspections body Estyn ranked the school as "adequate" and called for improvements.
A monitoring team on a follow-up visit in June found performance had decreased in some areas.
Last year's visit highlighted poor performance, particularly in Key Stage 4 at the school which has around 1,100 pupils aged 11-18.
Another target of improving the behaviour of a minority of pupils had been met only partially while the follow-up report also criticises the leadership at the school.
The school now has to produce an action plan. Inspectors will return in three months' time.
Chair of governors Paul Lucas said a number of changes had been put place since the visit last year with the school working closely with the local authority on the issues highlighted.
He said: "Only two months ago an acting head teacher was appointed and significant changes have been made to the academic structure within the school since that time.
"Estyn fully acknowledged the positive improvements over the two month period but they considered that there had been insufficient improvement over the preceding 12 months.
"Although disappointed at the outcome of this inspection we are determined to act upon the findings as quickly as possible."