Kent will need the equivalent of 10 new secondary schools to cope with a rising demand for places, a report by education chiefs predicts.
The pressure on places means an estimated 60 new classes will be needed across Kent’s existing 102 secondaries by 2018.
Kent County Council says population growth and inward migration are the key factors driving demand, after a period in which school numbers have either fallen or flatlined.
However, because the growth in demand will not peak until 2018 or until later, some secondaries remain vulnerable because of their existing low numbers.
These include 23 grammars, which KCC says are smaller than their ideal size and may need emergency funding to tide them over until the demand for places increases.
They are considered more vulnerable partly because they have generally fewer children benefitting from the pupil premium.
And the same issue is affecting 17 non-selective schools, where their intake in Year Seven - the first year of secondary school - is below 120 pupils.
According to KCC, schools carrying “a large number of surplus places must be considered vulnerable - even if their medium and longer term prospects are good.”
Of these smaller schools, several are academies and KCC says it is discussing ways of helping them financially until demand for places picks up.
KCC education director Patrick Leeson said: “This is a big, big issue for us. At the moment, we have a situation whereby if some of that is going to be delivered by expanding schools, a good number of those that we would want to expand are having serious financial difficulties and are under-performing.”
Cllr Roger Gough said: “What we have is a perfect storm of factors...we have been considering this for some time as a number of critical factors are coming together at the same time.”
The forecasts follow a squeeze on primary school places in the last few years in Kent, which is now filtering through to secondaries.