A nine-year-old boy has written to Prime Minister Rishi Sunak telling him his parents feel “failed and forgotten” as he pleaded for better support for disabled children and their families.

Nate Courtney, who is autistic, told the country’s leader he feels “sad” due to his parents having to “fight for everything” for him and his disabled sister.

The letter comes as a survey suggested just one in five parents of disabled children felt their family received the support needed to enable their child to fulfil their potential.

The results, based on 2,200 responses from parent carers, showed that only one in seven said their disabled child had the correct level of support from social care, one fifth from health services and a third from their education setting.

The Disabled Children’s Partnership (DCP), which ran the survey between October and November last year, said parents are being left to fill gaps left “by underfunding of official provision” and families are facing “relentless” stress.

The organisation – a coalition of more than 100 organisations campaigning for improved health and social care for disabled children, young people and their families – has previously reported that parents of disabled children have had to give up employment or have lost their careers entirely.

It has also already warned that the Government’s plan, announced last week, aimed at ensuring children with special educational needs and disabilities (Send) can get the help that they need earlier “falls short” of the urgent reforms needed to address the “crisis” in support for children and their families.

Nate, from south-west London, has written to the Prime Minister to tell him of his own family’s struggle for support, as his parents care for him and his sister, who is also autistic and has a muscle disease which means she needs a wheelchair.

He wrote: “I feel sad. My Mummy and Daddy are tired because they always have to fight for me and my sister.”

Nate said his parents “are always going to lots of meetings, talking on the phone and write letters on the computer”, adding: “They have to fight for everything, even a wheelchair for my sister.”

Asking for help, the child added: “My parents feel failed and forgotten. Let our parents just be our parents so we can enjoy ourselves.”

In its report, published on Tuesday, the DCP said: “Once again, as we reported during the pandemic, it is disabled children and their families that will be disproportionately affected by the current social climate.

“Disabled children are not immune from the record-breaking waiting times, backlogs and workforce issues across health and social care.

“NHS data shows that the proportion of disabled children waiting for treatment is equivalent to adults, and disabled children waiting for equipment, such as wheelchairs, are likely to wait longer than adults.”

The organisation said as many as a quarter of parents have been told that their disabled child does not meet the threshold in order for a social care assessment, and those who do get an assessment “still face delays in receiving the support they were assessed to be needing”.

Stephen Kingdom, campaign manager for the Disabled Children’s Partnership, said: “Nate’s story brings to life the shocking statistics in our Failed and Forgotten Report. Both show that parents are filling the gaps left by underfunding of official provision. The stress on families is relentless.

“We welcome some elements of the Department for Education’s Improvement Plan but it doesn’t go far enough to ensure children receive the support to which they are legally entitled.”