One of my abiding childhood memories was being given my first wheelchair. Until I was six, I had to resort to a large buggy, a mass of translucent plastic frames and ugly grey wheels. It was through the charity Whizz-Kidz that I finally got my first wheelchair, a streamlined seat in midnight purple. I remember taking my newfound freedom to my local Morrisons, home of the shiniest floor in town. I had gone from being trapped in plastic to sitting in a rocket ship, throwing myself down the crisps and snacks aisle.

A decade later, I had outgrown the chair and my family were back to working out how we would pay for a new one – this time a pricier, electric wheelchair that cost at least £5,000. My mum wrote to the board of local charities, we saved what we could, and Whizz-Kidz again filled in the rest.

As an adult, two things have stayed with me: gratitude to the organisation that gave me my independence, and a niggling question. Why in modern Britain do families of disabled children have to turn to charity for help?

Turning to charity feels particularly disconcerting if you’re disabled​​. It’s reminiscent of the pre-welfare state era

There’s often a misconception that the state provides a wheelchair if you need one, when in reality it’s common practice for disabled people not to meet eligibility criteria or to be left languishing on waiting lists. Last week, analysis in the Health Service Journal (HSJ) showed more than 5,000 disabled children in England who needed a wheelchair were waiting more than the four-month target for it to be delivered. Wheelchair delays have a devastating impact on a child’s life, anything from preventing rehabilitation to inhibiting their ability to make friends, or even go to school.

This is a class issue as much as a disability one; while wealthier families will be able to find several thousand pounds to cover the cost of a wheelchair, those on a low income will find it next to impossible on top of rent, utilities and food. (Households with a disabled loved one are much more likely to be living in poverty.) That inequality is only being exacerbated by austerity measures that will see families with disabled children lose an average of £3,300 a year by 2022 according to analysis by the Equality and Human Rights Commission (EHRC).

It isn’t only disabled children who are going through this. Last month, the British Red Cross warned a UK-wide shortage of wheelchairs was leaving as many as 4 million people a year who needed a short-term wheelchair housebound and isolated; some of these were terminally ill. Others who use a chair permanently are being similarly let down.

The NHS wheelchair charter, which was drawn up by campaigners before being adopted by NHS England, states that access and provision should be equal for all, “irrespective of age or postcode”. However, a Buzzfeed investigation into wheelchair provision last year found tens of thousands of disabled children and adults were being denied NHS wheelchairs in England because of a postcode lottery in services; almost a quarter of people referred by GPs to wheelchair services are not being given any equipment at all. Staggeringly, the investigation found 96% of areas were missing their target to supply all wheelchairs within the 18 weeks guaranteed by the NHS constitution.

I routinely speak to disabled people who are having to use an outdated wheelchair after being turned down by the NHS – a wheelchair that can cause them pain, fatigue and muscle damage. Others have even bought a cheap one via Amazon – not equipment suited to their disability provided by medics but a £50 punt sourced on the internet. It isn’t hard to understand why people would go to such desperate lengths. Disability can already be isolating due to anything from inaccessible public transport to social care cuts; new research by Scope shows half of disabled adults feel excluded from society. If on top of this you’ve been turned down for a wheelchair, you can be trapped in your home.

Millions of patients denied use of a wheelchair Read more

Across the board, from social care to homelessness, charities are increasingly being asked to plug gaps in state provision, and wheelchair services are no different. Last year, I reported that disabled people were being forced to use crowdfunding platforms to raise money for their wheelchair; turning to strangers because the state has left them housebound. When I recently enquired about funding for a new wheelchair, I was told the waiting list in my area was at least three years for a chair “that could go outside”. Instead, I was handed a leaflet for local disability charities.

Having to turn to charity feels particularly disconcerting if you’re disabled. It’s reminiscent of the pre-welfare state “deserving” versus “undeserving” era, in which, rather than the security of healthcare that each of us is entitled to, disabled people in need had to rely on the whims of philanthropists when competing for charity. It should worry anyone who believes in taxation and a comprehensive safety net for all.

Whether one of the richest nations in the world can provide disabled people with a safe and suitable wheelchair goes to the very centre of questions about our ever-disintegrating social contract, a matter that will only become more pressing in the coming years as the NHS deals with continual underfunding and spending pressures. When as a society we can’t even take care of disabled children, we surely have a problem.

• Frances Ryan is a Guardian columnist