Any government has a moral obligation to support the most vulnerable and disadvantaged in society, and this must especially be the case for children and young people within our communities. And yet, tragically, too many young people are being exposed to a perfect storm of hunger, physical inactivity and social disconnection – with the latter in some cases manifesting itself, heartbreakingly, in knife crime. Both their physical and mental health are under attack.

Research by ukactive shows that children and young people suffer a loss in fitness levels of up to 80% over the summer holidays, with the fitness of those from low-income families falling 18 times faster than their more affluent peers. This mirrors “summer learning loss”. A report by the Education Policy Institute shows that schoolchildren who were eligible for free school meals for 80% of their time at school were on average 24 months behind their classmates, and it is estimated that 66% of the achievement gap can be explained by summer learning loss.

The research on holiday inactivity now sits alongside new figures from the Trussell Trust, which show that during the past year more than 577,618 three-day emergency food supplies were given to children in crisis in the UK, as well as the latest police statistics on knife crime – a record 40,829 offences in 2018, up 6% on the year before.

Against this landscape, we cannot ignore the bite of austerity, which has led to the loss of vital community assets. Between 2012 and 2016, 600 youth centres closed, 3,500 youth workers lost their jobs and 140,000 places for young people disappeared. This week’s local elections have reflected the plight of many local authorities desperately trying to provide support for communities, despite ever-challenging financial constraints, and where volunteers and charity groups deliver essential services.

During the school holidays, the effect is magnified. New findings released today by ukactive and ComRes show that 74% of UK adults believe there is a lack of youth facilities over the summer break, and 77% say there is a lack of places for children and young people to be physically active. Simply put, we are letting down the next generation.

It was with this background that we went to Downing Street on Thursday as part of a delegation to discuss the health and wellbeing of children and young people in our society. We arrived with both evidence and solution. Our group included Professor Rosie Meek, who last year led an independent review on the impact of sport in the youth justice system; Steve Howell, headteacher of the City of Birmingham school (the largest pupil referral unit in the country); and John McAvoy, an ex-criminal-turned-Nike athlete. Our message was clear: there are many causes of social injustice and there is no silver bullet, but we have something powerful that can play a major role in reversing health inequalities among young people.

Because while options for disadvantaged children and young people diminish, especially during the summer holidays, there is an answer that lies right on their doorstep. On average, children live within 2.4 miles of their school, with the average distance falling as low as 1.4 miles for those in inner cities, where levels of deprivation are higher. Research by Sport England shows that 39% of sports facilities in England sit behind school gates, yet the majority of these are inaccessible over the summer holidays.

The physical activity sector is asking for the keys to unlock school facilities over the summer, and use them as hubs for activities. We know the value of schools during term time, the essential development they provide for new generations in our society. But they have another use beyond that; using a model that puts no additional pressure on staff, resources or budgets; a model that pays dividends both in terms of financial rewards and children returning to school happier, healthier and ready to continue where they left off.

In 2018, ukactive and partners piloted this scheme, in which 24 schools across England and Wales hosted holiday clubs to help children and young people aged between five and 15 to stay active and healthy over the holidays. The clubs offered a range of activities tailored by age group, including sports, games and performing arts classes. They also provided nutritious lunches.

We’ve seen the impact that highly trained physical activity providers can have. For example, at Dallaglio RugbyWorks we send rugby coaches into alternative provision schools in deprived inner-city areas, using the sport to engender the confidence and teamwork for young people to take new opportunities in education and training. Providers using performing arts, games and other activities can also be highly effective.

Now is the time for action. What we present is a model that clearly helps to fulfil the strategies of multiple departments over recent years, such as Sporting Future in 2015. The government must demonstrate the urgency, courage and willpower to end the holiday hell for millions of children and their families.

We are calling for a commitment from all departments to work together, and for the government to back this proposal at the next comprehensive spending review, so that we can expand this model across the UK. Together, we can give every child and young person the opportunity for a healthy and happy summer.

• Tanni Grey-Thompson, a five-time Paralympian, chairs ukactive, promoting physical activity for children. She is a House of Lords crossbencher

• Lawrence Dallaglio, a former England rugby captain, is founder of Dallaglio RugbyWorks