Naomi Gwynne, from Lanarkshire, Scotland, and her twin brother Isaac had been eagerly waiting for the new park near their home to open.
But when it did, Naomi was frustrated that her brother couldn’t go on the swings, despite them being his favourite piece of equipment.
In a letter to the park builders, and tweeted to South Lanarkshire Council on Sunday 19 March, she wrote: “I like the new park but please could you make a disabled swing for it?
“Isaac my twin brother is too big for a baby swing and can’t hold on to the bars of the grown-up swings.”
”His favourite thing is a swing and we are both sad,” Naomi continued.
“Why did you forget about him? I have drawn a swing he would like, thank you.”
Naomi drew a swing with a metal seat on the letter.
The young girl’s mum, Miriam Gwynne, told Metro.co.uk that Isaac is visually impaired with a brain tumour.
“I read [Naomi’s] letter through tears as I suddenly realised she was right,” the mum said. “Her brother who has severe autism, a brain tumour and severe learning difficulties had no swing.
“I am so proud of her! She has autism herself, so to have though to write a letter is incredible.”
Gwynne tweeted the letter to the council and was chuffed when she received a response.
“We try to include different pieces of inclusive play equipment in each of our play areas to offer variety,” a spokesperson for the council replied.
“We have asked the designer to look into whether the existing swing frame can incorporate a disabled seat for Isaac.
“Thanks for letting us know about this.”
Gwynne tweeted to the council on 20 March: “Thank you for listening to my daughter.”
She told HuffPost UK she was “happy” they responded but disappointed the swings were not included in the first place.