Birmingham's social services chief is to retire after 14 years with the city council, it has been announced.
Strategic director Peter Hay has run social care services for the elderly and disabled since 2003 and has had two periods in charge of children's services from 2003 to 2005 and since 2013.
Children's services has notoriously been rated as inadequate since 2009 and, since taking over in 2013, Mr Hay has been overseeing a government-backed improvement drive.
Last year, watchdog Ofsted announced it was starting to see signs of progress despite continuing to award a failing rating.
Mr Hay will step down as strategic director at the end of March and spend three months working on some specific research projects for the council before retiring in July.
City children's services chief Cllr Brigid Jones said: "Peter could not have taken on the children's services role here at a harder time.
"Since then, he has overseen significant improvements both in children's services and in schools, both of which have been recognised by Ofsted.
"We have worked together through many very difficult challenges, driving through changes and improvements to children's services.
"He has been personally instrumental in securing a stable and motivated workforce and I shall miss his leadership, professionalism and unreserved support. It has been a true pleasure and privilege to work alongside Peter."
The children's services side of the job is being scaled back as the council establishes its new semi-independent Children's Trust to run its child protection service.
At the same time, more and more schools have become academies and left local authority control.
Mr Hay has been in continuous control of social care for disabled adults and the elderly since 2003 during a period of major cuts and transformation.
Labour cabinet member for social care Cllr Paulette Hamilton said: "Peter has made a real contribution to this remarkable city, overseeing improvements - in really challenging times - to health and social care.
"Peter is admired and respected among colleagues and partners, both at director level and those on the frontline.
"I have really enjoyed working with him and, on behalf of my colleagues and the wider city, I want to thank him for his service and wish him well in his retirement."
An experienced social worker, Mr Hay came to Birmingham in 2003 and successfully oversaw an improvement in children's services that saw the service gain a star rating in the 2005 national assessment.
When the children's and adults' departments separated, he took charge of the newly formed adults and communities directorate, raising it to a three-star service and, when they merged again in 2013, he became strategic director for people, responsible for all children's and adults' services.
He has also been advising the Government on national social care policy and was awarded a CBE in 2012.