The leader of Pembrokeshire County Council has written to ministers after the Welsh Government gave it an ultimatum over concerns at how it safeguards children.
In the letter, Councillor Jamie Adams promised a "wide-ranging" investigation into allegations that disruptive children had been locked in padded rooms at the Pupil Referral Unit.
He said that there had been "a marked improvement" in improving the level of scrutiny within the council, and encouraging council officers and front line staff to air their concerns.
Already I have observed a change in the Authority's culture, the strengthening of our safeguarding policies and procedures and a change in the approach of our senior officers.
I would like to place on record my admiration for our front-line staff who deliver, on a daily basis, critical services for children and young people in Pembrokeshire. The environment in which they work in challenging, and yet they consistently achieve good outcomes for the children who need our support.
The Audit Office says despite some improvements, underlying issues have still not been tackled and the authority needs more help.
The latest report into child protection services in Pembrokeshire finds that whilst there have been improvements, more needs to be done.
Council leader Jamie Adams insists it has made good progress, but accepts there is more to do be done to improve children's services.