The director of Norfolk's under-fire children's services last night said Ofsted was right to criticise education in the county – but said she would not resign voluntarily.

Lisa Christensen is in charge of a department which has been criticised both for its failure to challenge schools for a below-average performance and inadequate safeguarding of the county's most vulnerable young people.

Last night she held her hands up to the latest problems which were this week highlighted in a letter from schools watchdog Ofsted.

Regional director Sean Harford expressed 'considerable concern' at the number of schools not reaching a good enough standard and criticised the county council for failing to intervene quickly enough.

Ms Christensen, who has been director of children's services since 2002, said: 'I don't think Ofsted have got it wrong. We are behind the national average. That's the unarguable, inescapable truth.'

Children's services has also previously accepted the findings of a report by Ofsted that rated child protection as inadequate. While insisting some improvements had been made, Ms Christensen said she had taken on board concerns about inconsistency within the service.

But the director said she did not accept the idea that things had 'gone wrong' at the county council.

Ms Christensen, who pointed to Norfolk's outstanding special schools, successful youth offending team and youth advisory boards as examples of children's services' strengths, said: 'We are not a failing department, although we have got some very significant issues we need to sort out.'

For that reason, Ms Christensen said she would not be stepping down – but did not rule out the possibility of being asked to resign.

'I could say 'I think I have failed totally and I should go' but I'm afraid that's not my feeling,' she said.

'The county council will need to come to its own conclusions about things – whether they want a fresh pair of eyes – it's not for me to decide that.'

When asked if she felt the county council still had confidence in her to steer children's services in the right direction, she said: 'It's a bit difficult to tell at the moment. Once the county council leadership and cabinet port folio leaders are in place, things will become clearer.'

Norfolk County Council has plans in place which it believes will bring about improvements in both areas.

An improvement board has been appointed to help raise standards in child protection and a report called A Good School For Every Norfolk Learner – backed by £1m of funding – aims to accelerate the pace of improvement among schools and draw on the strengths of good and outstanding schools.