As a rule, hungry children do not tend to do very well at school. They're fidgety and disruptive. They struggle to concentrate. Their ability to learn is severely hindered when their developing brains are deprived of the fuel they need to function properly. Undernourished kids are more susceptible to illness and more likely to need to take time off from lessons to recover.

None of this is news to parents or education professionals. It's also unlikely to surprise anyone who's ever hit a mid-afternoon slump at work and realised they skipped lunch that day.

For school children though, the stakes are much higher. Eating properly can be the difference between acquiring the skills and qualifications needed to succeed in adulthood and falling by the wayside. Being able to sit quietly and listen attentively is often key to avoid being labelled as a troublemaker. Childhood malnourishment can also have a lifelong impact on a person's physical health.

UK children going hungry

Evidence suggests that tens of thousands of school-age children in the UK are going hungry. 83% of teachers say they see pupils arrive at school with empty stomachs. Almost half have spent their own money on providing breakfast.

Even more worryingly, means-tested free school meals are failing to ensure all children can eat a proper lunch. Research by the Children's Society found that many kids living in poverty were ineligible for the state-funded meals.

In London and other areas with high living costs, more than 60% of children below the poverty line were not eligible. Almost one in five teachers report they've given pupils money for lunch out of their own pockets. What's more, nearly a third of parents with an income of less than £25,000 say they've skipped meals so they can afford to feed their kids.

In this context, the news that George Osborne is considering axing the Universal Infant School Meals scheme is deeply troubling. Whilst by no means a complete solution, the provision of free meals to all infant pupils, introduced under the last coalition government, has been a ground-breaking step towards solving the problem of childhood hunger.

Universality ensures that not a single child falls through the net. Whatever their circumstances, no pupil in their first three years of compulsory education is left with a rumbling tummy at midday. At least, not for the five days a week they attend school during term-time.

If anything, the government should be looking to expand the programme to also cover older children. Providing food at breakfast is an additional possible improvement. Scrapping the scheme altogether would be a deeply regressive move.

Schools left struggling

Implementation of UIFSM has not gone as smoothly as it ideally might have. Some schools have been left struggling to provide hot meals as they wait for government grants to upgrade their kitchen facilities.

The system of allocating extra funding to schools based on the number of pupils receiving means-tested free meals needs updating, as many parents are not bothering with the rigmarole of claiming now that their children are being fed either way. However, such practical hiccups should not be mistaken for evidence of a problem with the general principle of universality.

Similarly, critics who argue that means-testing allows resources to be allocated more efficiently fail to properly appreciate the benefits of a universal approach. Even if means-tested eligibility was expanded to include families on slightly higher incomes, it would be impossible to ensure that every child was being properly fed under this system.

Sometimes, parents' failure to provide food has more complex causes than simple lack of income. Debt, mental health problems and addiction are just a few examples of other factors that can lead to children going hungry. With budget cuts reportedly forcing councils to raise the threshold for escalating child protection investigations, the number of such cases is unlikely to decrease anytime soon.

Universality is already a bedrock of some aspects of the UK's post-war welfare state. We're especially proud, and protective, of our National Health Service. Particularly, its unconditional provision of care that is free at the point of delivery. Those who can afford to contribute more towards its cost do so as part of their tax bill, not when they're lying in a hospital bed. It's the simplest, most effective way of guaranteeing that nobody is left without essential healthcare.

Likewise, the unconditional provision of Winter Fuel Allowance to all elderly people is accepted as the best way of ensuring nobody who needs it is left struggling.

As with many public spending decisions in wealthy countries, the issue of cost is actually largely a question of priorities. If something is considered truly essential, money can generally be found. No government that decides to raise the inheritance tax threshold - a tax cut that can't be justified as economically beneficial - can claim its hands are entirely tied when it comes to such matters.

A functioning society should protect all of its most vulnerable members, whatever their age and circumstances. What reason is there to consider ensuring children don't starve as less important than ensuring pensioners don't freeze?