Setting up schools in empty warehouses or disused superstores? Converting offices into classrooms? It may sound desperate, but in some parts of the country demand for primary places is so great that every option is being explored. “We are building new schools, and expanding others,” says Barking and Dagenham councillor Rocky Gill. “But we are also having to consider leasing commercial space and turning it into classrooms.”

Rising birth rates mean that, nationally, 500,000 primary places must be created over the next six years - a 14 per cent increase. But in many areas the baby boom has coincided with other factors such as economic migration, urban regeneration and immigration.

In Barking and Dagenham, east London, applications for primary places have risen by 12 per cent in the past year alone. “This is not a one-off blip,” says Mr Gill. “Families are moving out of inner London in large numbers, and that is likely to continue.”

This year every child in the borough has been accommodated, but Mr Gill admits the situation is not ideal, with 28 temporary classrooms in use and schools operating on split sites.

Many heads across the country have been told their schools will have to grow but do not yet know how quickly or by how much. At Little London Primary in Leeds, for example, there is a proposal to move from one-form to three-form entry, but no decision has been taken. A one-off “bulge class” next September remains a possibility. “Not knowing makes it difficult to plan,” says head Jill Wood. “We are working around seven possible variations of what might happen.”

The school has to turn away children who live on its doorstep, so expansion seems an obvious step. But the situation is complicated by the fact that there are still spare places in other parts of the city. And not all local parents like the idea of their small, friendly primary ballooning from 210 pupils to 630.

“There is a PR battle to be won,” says Ms Wood. “But the worst thing is the uncertainty. You can put a temporary classroom up overnight, but budgets and staffing need a lot more forethought. Until a firm decision is taken, we are in limbo.”

And that is not a helpful place to be, with teacher recruitment likely to be more difficult this year than in the past few years. “Heads looking for new staff should not leave it too late,” says job market expert John Howson, director of Education Data Surveys, part of TSL Education. “Until now there has been a surplus of primary teachers, but it would not be a surprise to see shortages beginning to develop in certain parts of the country.”

So could local authorities have done more in terms of forward planning? Mr Gill thinks not. “There has been a massive demographic shift,” he says. “No one could have predicted it. But we have to respond and we can only do that with proper funding from central government. It is a disgrace that so many children are being taught in temporary classrooms, but we have been left with no real alternative.”

Rising roll facts

- The number of primary school pupils is projected to increase from 4 million to 4.5 million by 2018;

- government figures suggest 500 new schools will need to be built;

- areas experiencing a surge in demand include London, Bristol and Essex;

- some parts of the country - particularly rural areas - still have surplus places.