A distraught teenager is appealing for help to find her GCSE coursework after a charity shop inadvertently sold a dress she had spent months creating for just £5.

Grace McCallum had been thrilled when she found out her lovingly-crafted Minnie Mouse dress had been specially picked to go on display in the Didsbury Village Cancer Research store on Friday, June 23 as part of the Didsbury Arts Festival.

But on Saturday when she and mum Clair went to take a look at the fruits of her labour, they were shocked to discover it missing, and hoped it had just been moved to another part of the shop.

But two days later staff at the Wilmslow Street store confirmed the dress had in fact been mistakenly sold by a well-meaning charity shop volunteer for a mere five pounds.

Clair and Year 11 pupil Grace, who attends the Barlow RC high school, are now desperately appealing for the return of the dress which counts for 60 per cent of her product design GCSE - as they don’t know if examiners have even had the chance to mark it.

Comedian Jason Manford has even shared the family’s appeal on social media with his 255,000 Twitters followers to help try and reunite them with the unique garment.

Sixteen-year-old Grace, who lives in Cheadle, said: “I was upset after all the work and time I had put into it.

“I couldn’t understand how it was sold as it was marked up as a school item.

“I will be gutted if it hasn’t been marked.”

Cancer Research has apologised for the mistake and say they are urging their customers to spread the word to track the fancy dress outfit down.

Mum Clair, who works at Macclesfield firm Ace Garage Door Specialist, said: “I know how hard Grace has worked on the dress, staying late after class until after 6pm, missing out on dinner breaks.

“Grace is so upset, she couldn’t believe that it had actually been sold to someone. She said ‘it’s got to be a joke, they can’t have sold my GCSE coursework’.

“And now she’s panicking because she doesn’t know if it has been marked or whether it will need to be re-examine it, we don’t know if the examination board can go off just a photograph of it. She’s absolutely gutted.”

Mum-of-four Clair added that Grace had initially been delighted when her dress was one of the outfits chosen by a school governor to go on display in charity shops for the Didsbury Arts Festival.

She said: “Grace was really pleased to be picked but the teacher was about doubtful about letting them go. We went on the Saturday to take a peek in the front window and it wasn’t there so we just assumed it had been moved.

“We went back and there was still no sign, so I phoned only to be told that one of the staff members had sold it by mistake. But there was actually a label on the dress with the school emblem on it with the child’s name and saying it’s part of the festival.

“They only sold it for £5, that’s the kick in the gut.”

The special black and red polka-dot dress was made by Grace as part of a product design project to create a children’s dressing up outfit, and is a unique design.

Clair added: “It’s quite distinctive. The front of it’s got a bow on the neck and it’s got the gloves of Minnie and Mickey Mouse on the pockets, with a ra-ra lining in the skirt.

“When she first brought it home I couldn’t believe she’d made it, I was really surprised by how good it was.

“I think it’s a genuine mistake it’s been sold but we desperately need to get it back for Grace’s GCSE.”

The family hope that if their appeal is shared widely enough they’ll be able to get the dress returned safely.

Alison Barbuti, Cancer Research UK spokesperson for the North West, said: “Our Cancer Research Didsbury shop is one of a number of shops in the village asked to display local artwork as part of the Didsbury Arts Festival. Unfortunately on Saturday one of the items on display in our shop, a child’s Minnie Mouse dress was mistakenly sold by one of our volunteers who thought it was part of our stock.

“As as soon as we realised the error we tried everything we could to try and trace the item. We put a poster in our shop window urging the customer who bought it to return it in exchange for a full refund and having been asking all our customers to spread the word.

“We are in contact with the lady whose daughter designed the dress and we really hope it will be returned as soon as possible. We apologise profusely for any upset caused.”