Hundreds of thousands of extra school places will be needed by next year, the government’s spending watchdog has warned.

In a report published last week, the National Audit Office said the government was putting billions of pounds into establishing more places, but suggested that the Department for Education needed a better understanding of the costs and the impact its funding was having in local areas.

The heightened demand for primary places follows a leap in the 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.

By September 2014, an estimated 256,000 extra school places would be needed, the report said.

Number of infant classes of 31 or more students*

2007 - 660

2008 - 720

2009 - 830

2010 - 1,000

2011 - 1,370

2012 - 1,510

Number of children in infant classes of 31 or more students

2007 - 23,200

2008 - 24,800

2009 - 28,900

2010 - 31,300

2011 - 43,100

2012 - 47,300

Number of students per class on average at key stage 1

2007 - 25.6

2008 - 25.7

2009 - 26.2

2010 - 26.6

2011 - 26.9

2012 - 27.2

* Class sizes in Reception and Years 1 and 2 are legally limited to 30 students per teacher. Schools are only allowed to breach these limits in certain circumstances.

Source: Department for Education, 2012.