The report highlights the social services department's failure to fulfil some of its statutory duties.
New executive director of social services Penny Thompson said: 'The review highlights serious issues that the council does not consider to be acceptable. However, the review was carried out last spring, since when things have improved considerably.'
Sheffield's three-year plan includes:
- Assigning a social worker to each child in care or on the child protection register, with a review every six months.