The head of children's services in Norfolk is to step down, days after the county's MPs called for a change of leadership at the under-fire department.

Lisa Christensen, Norfolk County Council's director of children's services, today announced she would stand down from the role and retire from the authority from July 18.

It comes after her department came was blasted by Ofsted for the way it safeguards vulnerable children and for not intervening quickly enough in struggling schools.

And yesterday figures from the schools watchdog showed Norfolk, along with Suffolk and Cambridge were among the worst 10 areas in the county for performance by poorer children in primary schools.

The county's MPs last week issued a statement calling for an interim board to be brought in to take over the running of children's services - which amounted to a vote of no confidence in Ms Christensen.

The 56-year-old, who has worked at County Hall since 2002, is taking early retirement and will receive two months' gross salary in lieu of notice. which works out at £23,248.

The council will make a one off compensatory payment to the Norfolk Pension Fund of £116,398. That money goes to the Norfolk Pension Fund rather than to Ms Christensen.

She said she hoped her departure would mean her 'talented and dedicated colleagues' could pull together to help deal with the problems facing the department without the glare of potentially morale-sapping continued media criticism.

She said: 'It has been a privilege to have worked in Norfolk for nearly 11 years through a period marked by fundamental and continuing policy changes and increasing financial stringency for the public sector.

'I have been proud, and lucky, to have worked alongside colleagues in the county council and throughout the public and voluntary sectors in Norfolk, and nationally, whose dedication to achieving better outcomes for children and young people is evident every day.

'During this time, the delivery of education and other services for children and their families in Norfolk has been transformed. And the evidence is that the actual outcomes for our children and young people have improved and risks have lessened.

'But many challenges remain and in some key areas of this large and complex service, improvements have not been fast enough, or consistent enough. I know securing them is a firm priority for the council and all our partners.

'Together, we are engaged in a mutual effort to deliver better results for our children and young people and this has renewed vigour following recent inspections.

'I hope that public support and recognition for frontline workers such as teachers and social workers, and those that provide support and leadership to them, will be to the fore in the coming months.

'I have always believed constructive analysis based on facts to be essential for healthy and accountable public services.

'I hope my decision to leave the county council now, secure in the knowledge that it is in a good position to move forward positively, will enable my talented, and dedicated colleagues to move forward without the distraction of continued critical media attention which is in danger of sapping morale and compromising the very work we are engaged in.

'I am very grateful for the many messages of support and appreciation that I have had over the last few weeks from respected colleagues from all sectors.'

James Joyce, children's services cabinet member for safeguarding, said it was the right decision, but blasted the MPs for their 'grandstanding'.

He said: 'I respect Lisa's decision and think it is the right one, especially in light of the very personalised attacks made on her of late, and for the service going forward.

'On behalf of the authority, I thank Lisa for her very hard work on behalf of all Norfolk's children and young people over the past eight years – a period during which we have seen improvements in many key areas of the services that she is responsible for.

'It is also one that has seen the council recognised nationally for some innovative areas of excellence in children's services – for example our Youth Offending Service and our Youth Advisory Boards.

'Of course, we know there is more to be done, that is why this new administration has made services for children and young people its very top priority and allocated two cabinet member roles to the children's services portfolio.

'It is also why we made it a priority to review matters quietly, but effectively since we took office, ensuring a robust improvement plan was put in place.

'Norfolk's MPs were aware of this and that is why we felt their sudden grandstanding was not just unhelpful, but irresponsible.

'Plans to recruit a top level interim director of children's services are now well underway and we expect to be in a position to announce the recruitment shortly. In the meantime, the acting managing director is providing additional supportive leadership to the management team.'

Ms Christensen has worked at Norfolk County Council since October 2002, first as director of social services and then, in 2005, of children's services.

Her career in public service spans 34 years – in local government, the voluntary sector and the NHS.