Norfolk's children's services department is still not giving children a consistently good enough service, according to watchdogs, who criticised leaders for not being 'ruthless enough in pursuing improvement'.

While Ofsted inspectors said there had been 'positive movement' in some areas of the department, which has twice been rated as inadequate in recent years, they said the overall pace of change was slow.

The Norfolk County Council department – tasked with looking after the most vulnerable youngsters in the county – was rated 'inadequate' when it was inspected in 2013 and, when inspectors returned last year, the rating was once again 'inadequate'.

Three inspectors from Ofsted, as part of the watchdog's monitoring regime, revisited the council for two days in October and today published their findings.

The letter stated: 'While there has been positive movement in some areas of children's services, the overall pace of change is slow.

'Leaders have not been ruthless enough in pursuing performance at all levels. Difficulties recruiting high calibre staff, and poorly developed strategic planning and performance management, have hindered the authority's efforts to transform services.

'As a result, children and young people are still not consistently receiving good enough services.'

Inspectors said the quality of information and level of detail provided by partner agencies in contact and referral forms was too variable and acknowledged the council was trying to strengthen leadership of the multi-agency safeguarding hubs.

They said the judgement of some social workers was 'not sharp enough' and some were 'too quick to accept at face value what children or adults say', with analysis 'not sophisticated enough in weighing the child or young person's wishes and feelings against all the other information gathered in assessments.

They said: 'In two of the six cases tracked by inspectors, a lack of professional curiosity resulted in social work interventions which were incomplete or ineffective'.

But they found 'appropriate action' had been taken to tackle high case loads in Norwich - which had previously led to a backlog of 70 assessments of children awaiting completion or sign off.

There was criticism that children were not getting quick enough health assessments and 'significant variations' in performance across the six social care teams across the county, with inspectors attributed to 'potentially invaluable' information not being used.

And they said: 'Under-investment in performance management information means that senior managers responsible for managing a multi-million pound service do not have the information they need to do their job effectively.

'Although reports contain a substantial amount of data, it is not possible to identify patterns and trends. This undermines transparency and makes it extremely difficult for senior managers and leaders to hold their managers and staff or each other properly to account.'

Inspectors acknowledged a new set of performance management reports was about to be piloted.

Norfolk County Council has been contacted for a response.