Tens of thousands of extra school places will be needed by next year amid a continuing surge in demand, the spending watchdog has warned.
Despite more than 80,000 extra primary spaces being created in the last two years, there are still signs of a real strain on school places, according to a new report by the National Audit Office (NAO).
It says that the Government is pumping billions of pounds into establishing more places, but suggests that the Department for Education (DfE) still needs a better understanding of the costs, and the impact its funding is having in local areas.
The report suggests that the heightened demand for primary school places is partly down to a rising birth rate - the rise in the number of children born in England between 2001 and 2011 was the biggest 10-year increase since the 1950s.
Between 2006/07 and 2011/12, the number of four-year-olds starting reception classes rose by 16%, it says. It warns that by September 2014, an estimated extra 256,000 primary and secondary school places will be needed to meet the demand. Of these, 240,000 are required in primary schools, with more than a third (37%) needed in London alone.
These extra places are still needed despite a net increase of almost 81,500 places which were created between 2010 and May 2012, and the DfE increasing the amount of funding it gives to local councils to provide spaces.
How many places will be required in the future is uncertain, the NAO says, but it is expected that more will be needed beyond next year. The NAO's report says that while the DfE considers that local councils are meeting their duty to provide enough school places, the watchdog found signs of pressure on the system.
More than a fifth (20.4%) of primaries are full up, or over capacity, while the numbers of children being taught in large infant classes of 31 pupils or more has more than doubled in five years. This has gone up from 23,200 in 2007 to 47,300 in 2012, the report says.
And an NAO survey of local councils found that more than a third (34%) said that rising demand for school places has had a "significant impact" on the average time a child spends travelling to school.
The report concludes: "The Department's assessments of funding required to meet expected demand are based on incomplete information."