MPs have warned that under-performing schools could be forced to expand to deal with a chronic shortage of places for children.
Local councils may have to make decisions that affect the quality of pupils' education in the rush to provide enough school places, a new report by the Commons Public Accounts Committee (PAC) said.
Buildings such as libraries or music rooms could be turned into classrooms to meet the demand in areas facing a squeeze on places, it added.
The committee is the latest group to raise concerns about a lack of school places.
More top news
Parliamentary inquiry finds thousands of children could fall prey to sexual exploitation and gangs because of flawed warning systems.
David Cameron said the June 23 referendum is the most important vote young people will place in their lifetimes.
Plan would leave steelworkers worse off in retirement - but not as worse off as those in other pension schemes.