Summer holidays are "exceptionally difficult" for children in many low-income families and can have a detrimental impact on their health and learning, new research suggests.
The study found children's health may be put at risk through isolation, extended periods of inactivity and malnourishment, as many lose access to free school meals and suffer "holiday hunger".
The University of Glasgow paper, a review of UK-wide research, found children from poorer families also have less opportunity to take part in the enriching activities that their better-off peers take for granted and their learning "stagnates and declines".
The research suggests the lack of educational and developmental opportunities enjoyed by more affluent children means the long summer break may be one of the most fundamental contributors toward the attainment gap between richest and poorest children, accounting for almost two-thirds of the gap by the time children reach the age of 14.
Nicolas Watson, of the Institute of Health of Wellbeing Professor at the University of Glasgow, said: "The long summer holidays can offer children the chance to have new experiences, opportunities to play, relax, create memories and develop essential social skills.
"While this is true for many children, for some the school holidays are a stressful and impoverished period of isolation, boredom and inactivity.
"For low income families, summer holidays often entail increased financial pressures, food insecurity, poor health and exclusion from culturally enriching and healthful activities."
Professor Watson is calling for a system of social protection to be put in place to negate the impact of poverty during the summer holidays, which could be in the form of centres where children can take part in enriching activities in a safe environment with good quality childcare, where they are also fed.
He said: "These children need help immediately. First and foremost, steps must be taken to address the national problem of food insecurity to ensure children do not go hungry or become malnourished during the school holidays.
"Second, providing accessible, good quality childcare that meets the diverse needs of families is vital if children's learning and wellbeing is to be supported, while enabling parents to pursue better paid and more secure employment.
"Third, although there is a substantial amount of evidence to support the claim that summer learning loss is a problem - and a particular concern for low-income families - there is a lack of research on the long term impact upon attainment and life outcomes, a gap that must be addressed through rigorous academic scrutiny."
The paper, The Cost of School Holidays for Children from Low Income Families, is published in the journal Childhood.
It concludes summer holidays are an "exceptionally difficult period" for many low-income families and calls for action to tackle the problem.