With the number of pupils entering primary schools due to rocket in the next few years, the issue of class size is back in the news.

Niall Bolger, chief executive of the London borough of Sutton, suggested that increasing infant class sizes to 32 pupils could be a “pragmatic compromise between educational viability and financial prudency”, although this is not council policy.

The limit of 30 pupils in infant classes was introduced by Labour in 1998 and became a legal requirement in 2001.

Research supports the move to smaller class sizes for the youngest children, but studies suggest that this is not the most cost-efficient way of improving outcomes for older children.