The report from the Office for Standards in Education, Ofsted, says the local education authority does show "signs of continuing improvement".

But it also criticises Kent's provision for children with special educational needs. It says Kent takes too long to issue children with statements of need, and does not monitor how its schools target resources, so that pupils and their parents are "not consistently well served".

It is the remarks on selection that are the most charged. Kent is England's biggest education authority and one of the few to retain the 11-plus exam. Campaigners against the selective system plan to use new rules to challenge it in the county through ballots of parents.

Ofsted says the system is complex. The county has 15 local education authority grammar schools, each of which uses one 11-plus exam. But there are 18 grant maintained grammar schools running their own admissions using at least three different exams.

'Unacceptable'

Children are sitting the exams this week for places next September but may not know until July which school they are going to, because of the appeals process. What Ofsted calls these "unacceptable delays" lead to planning problems for the high schools which take children who are not selected.

Appeals can come from primary school headteachers to grammar school heads, on behalf of their own "borderline" pupils, and parents can appeal to panels of councillors.

Ofsted criticises the lack of consistency this leads to across the county. It says the education authority "cannot be sure there is equity in the process" and urges Kent to take steps to ensure that the selection process is "transparent and fair to all pupils".

Kent's Education Chairman, Paul Carter, said the authority viewed Ofsted's comments as a vindication of its efforts to "streamline" the 11-plus.

"This report will help us to do that, and arrive at a common test at age 11," he said. "We are already consulting with schools on bringing the exam forward in the year to give parents certainty of placement earlier in the year."

One primary headteacher who is against selection, Eamonn Norton of St Peter's Primary School, Sittingbourne, said Ofsted's comments were "gold dust".

"The way selection works in Kent is a disgrace," he said. "The whole system is flawed and has no credibility amongst professionals.

"We have an 11-plus because of politics. It has nothing at all to do with education. This report brings home the truth of the matter. It only confirms what we have been saying for a long time."