Labour’s pledge to provide free school meals for all primary pupils would cost £950m a year, new analysis has revealed.

Research by the Institute for Fiscal Studies (IFS) found the proposal would generate direct costs of £800m a year for the Government. It would also result in an extra £150m a year in extra funding for the devolved nations through the Barnett Formula.

The IFS also said the extension would require an upfront cost of £225m to upgrade school facilities.

The briefing stated: ‘Extending free school meals to all primary school children would cost around £950m each year. It would not directly benefit the poorest children, who are already entitled to free lunches.

‘While there is some evidence it might raise attainment overall, we don't understand how or why, and so the effect of extending this nationwide is uncertain. In the context of constrained public resources it is important to be much clearer about effectiveness before spending a large amount of money on a new universal entitlement.’

The IFS pointed to a pilot project undertaken in 2012 that found extending free school lunches to all Year 6 students in Newham and Durham helped children make an extra two months’ progress over a two-year period.

However, researchers warned that other policies could provide a cheaper and more effective way of improving education and health outcomes. For example, breakfast clubs in disadvantaged schools could deliver similar academic benefits to universal free school meals at a tenth of the cost per pupil.