Across the country, skirmishes are taking place at school gates. Teachers have battened down the hatches of their packed classrooms against outraged parents who cannot understand why their offspring have not been allowed in. Meanwhile, directors of education plead helplessness.

Desperate shortages of school places might be more familiar in developing countries, but in some areas of the UK local authorities and headteachers are having to take urgent action to accommodate local pupils. Temporary huts are springing up as classrooms.

In London, 16,000 children will struggle to find primary school places and a further 15,000 over the next five years will be educated in so-called bulge classes.

Meanwhile, more than 2,000 schools have closed in the past decade and this shows no sign of slowing - especially with promises of government cash for reducing surplus places.

Trying to predict pupil numbers has become an increasingly sophisticated art. A rising birth rate, immigration and an exodus from the private sector have all been blamed for the lack of spare desks - but in fact it is the newly found parent power of this generation that could be causing the trouble.

Not so long ago, children went to their local school and everyone was content - or so it might appear.

Then inspections became more judgmental. The idea that some schools were better than others became firmly lodged in the public consciousness.

Experts say this has had a dramatic effect on their fortunes in ways not yet realised. Families started moving to areas with “good” schools, causing house prices to rise and making the location a no-go area for those with lower incomes. Other schools became unpopular and their pupil numbers declined.

And, of course, teachers are now not allowed to accommodate class sizes of 40 or 50 - common in the 1960s and 1970s - which makes expansion difficult in the event of a population explosion.

Moves to review school places started in the 1980s when planners realised the effects of a steady decline in the birth rate.

The desertion of young families from the countryside and the high cost of keeping small primaries open provided a strong defence to councils which closed them. But many urban schools are also facing the axe.

And there can be both shortages and surpluses in the same city. In Bristol, for example, some schools have surplus places while at eight schools temporary clasrooms are having to be built.

There is a lack of space in schools in Bradford, south Reading, Sussex, Sheffield, Southampton and Birmingham.

Human geographer Danny Dorling, from Sheffield University, is sceptical about the impact of the birth rate on schools.

“I think the biggest impact has been smaller class sizes and the rigidity that has caused, as well as the assumption of parental choice,” he said.

“In the past, parents were most concerned about their children falling ill, but that paranoia has now transferred to their performance in school.

“The admissions system is simple and worked for years, and the concept of a local school is how Europe works. All you need to do is provide schools where children are.”

It all seems so simple. While the Department for Children, Schools and Families says it has a “presumption” against closing rural schools, it seems that policies might be hastening their demise.

For example, they must demonstrate that they can manage school demand - including getting rid of excess unfilled places - before they receive money as part of the primary capital review programme. The scheme aims to refurbish or rebuild half of all English primary schools by 2022-23, and many of those given funding have chosen to wield the axe, including Dorset and Warwickshire and urban areas such as Gateshead, Bristol and Hartlepool.

Originally, 23 “pathfinder” authorities were chosen to share Pounds 150 million of funding this academic year. Of these, three proposed closing schools to reduce surplus places - Kent, Manchester and Torbay.

In total, 41 local authorities have received full primary capital review funding.

In Bristol, the decision to close two small primary schools has been described as shortsighted by heads, who say council officials have taken no account of expected population rises in the area, the performance of the schools or the views of parents.

For example, two of the city’s smallest schools have been chosen for closure - St Pius X RC Primary in Withywood, and Stockwood Green - even though they are improving and pupil numbers are growing. Larger schools which have more surplus places and worse results will be kept open. Another primary, St George’s CofE, has been given a stay of execution.

There are no places left at nearby schools, and those marked for closure have been picking up youngsters who move to the area. The very small numbers of parents who have asked about places at neighbouring schools have been told there is no room.

Critics of the council’s strategy point out that St Pius has managed to boost pupil numbers from 80 to 120 in just two years since the school came out of special measures, and the local diocese spent around Pounds 250,000 on improvements in the past year.

Head Tony Halloran, interim chairman of Bristol Primary Headteachers Association, said: “The council thinks larger schools are more effective and efficient and they will attract top-class leadership - this is quite insulting to those of us who work in smaller schools.

“It seems to me this is just a numbers game and the aim is to remove choice.”

At St George’s Primary, children will have to move half a mile down the road to another church school with more than double the number of pupils.

“We feel the recommendations of the review flout many government regulations. They take away parental choice as well as a much-needed foundation stage in the area,” said head Clare Gundry.

David Michel, NASUWT secretary for Bristol, said teachers were “very concerned” about their futures. Some could be offered jobs at other city primaries, but this depends on the co-operation of governing bodies.

“It’s a difficult situation. If you keep schools open which are not economically viable, something has got to give elsewhere. The teachers in these schools are unfortunately being held to account by geography,” he said.

Other councils, however, have a different approach. They are choosing to keep open half-empty schools because population changes are expected in the future.

For example, Greenwich has eight primary schools with 25 per cent or more surplus places, but officials think the number of local children will grow.

Councillor Heather Wells, portfolio holder for children and young people’s services at Rutland County Council, said education bosses have had to be “creative” with budgets after it was decided to keep the area’s smaller schools open.

But she is adamant that closing them would have had a devastating effect, equivalent to shutting a post office or village shop.

“It would have been very easy for us to close schools. It’s a quick win financially and I can understand why people do it, but we are very committed to keeping them open because they are part of community life,” she said.

Schools with surplus places are being refurbished so they can be shared with the community - which means extra children can be accommodated in the future, if needed.

“People do tend to drift to particular schools, but this moves around in time and others become the flavour of the month. We try to make all our schools successful,” Ms Wells said.

The DCSF says that it is up to local authorities to “balance supply” and set “realistic targets” for surplus places after assessing local circumstances. However, with a raft of policies that so often pull and push councils to both open and shut schools, it is clear that it is really not that simple.

Surplus to requirements

In 1999, there were 26,052 schools. By 2009, the number had dropped to 24,685.

- In 2007, there were 792,125 surplus school places in England: 514,376 in primaries and 277,749 in secondaries.

- Between 1994 and 1999, surplus places in primary schools fell by 23 per cent. Since 1999, the number has steadily increased to 12 per cent of total capacity in 2007.

- In secondary schools, surplus places steadily fell from 14 per cent of total capacity in 1994 to 6 per cent in 2004. The number had risen to 8 per cent in 2007.

- Government guidance is that no school should have more than 25 per cent of places surplus, and ideally the number should be 10 per cent or less.

- The population of the UK is set to rise by 10 million by 2031. Birth rates were highest in the early 1960s, fell sharply in the 1970s, rose slightly in the early 1980s and have been rising since.