“To my great embarrassment, I’ve just discovered that I have been holding onto your novel, HACKER, since February 1990”, read a letter to Noughts & Crosses author Malorie Blackman from the senior commissioning editor of Simon & Schuster, dated nearly two years later. “I’m afraid we are not publishing any teenage novels in the near future”. The printed letter, addressed to “Marlorie”, with the extra “r” struck through in pen, was one of 82 rejection letters the writer received before her first book was published.

Hole-punched and stored in a ring binder, the letter is now on display at a British Library exhibition about Blackman, who has gone on to write more than 70 books for children and young adults, including the million-selling Noughts & Crosses series. The rejections folder is one of the artefacts that the author is most excited for the public to see, she says. “I hope that does encourage people.”

In 1989, amid the rejections, Blackman queued up for hours at a signing for Alice Walker’s novel The Temple of My Familiar. Blackman told Walker about her struggle to publish, and asked Walker to write “Don’t give up” in her copy. The inscribed book is also displayed in the exhibition. “For most people,” Blackman says, “especially if you’re in a creative world, the journey isn’t always straightforward, and so sometimes you just have to hang in there”.

The exhibition traces Blackman’s young adulthood: the Lewisham homeless shelter she lived in aged 13 is pictured; the comics she turned to as a “shield against the real world” are displayed. In the local library, which she says “saved my life”, she would read novels, including classic fiction – the likes of Jane Eyre. Later, at 22, she came across Walker’s The Color Purple – the first novel she had read that was written by a Black author and featured Black protagonists. “It had a profound effect on me,” says Blackman. “She was a Black woman author. They existed!”

Blackman wanted to study English at university and go into teaching, but her career adviser told her that “Black girls don’t become teachers”. She began studying business instead, but when her studies were interrupted by illness, she left for a job in computing. An Acorn BBC Micro computer is displayed, along with a picture of Blackman sitting upright at the one she owned, her red shirt matching the model’s distinctive red function keys.

In 1990, when she was 28, Blackman published her first book, Not So Stupid!, a collection of horror and science fiction for young adults. Throughout the 90s, she wrote tens of books for children. These included Whizziwig, a novel about two boys who befriend a small pink alien – it was adapted for television, and the furry puppet that Blackman was given at the end of filming is one of her favourite items on show.

Another early adaptation, of Operation Gadgetman!, disappointed Blackman. She had sold the film rights of the book – which featured two Black girls and one white girl as the protagonists – to finance her writing career. Yet, “watching the finished film was a revelation”, she wrote in the Guardian in 2006. “My three girl characters had been turned into boys, which I didn’t mind so much. And each boy was white. That I did mind.”

Blackman first wrote explicitly about race in her 50th book, Noughts & Crosses, set in an alternative Britain in which dark-skinned Crosses rule over light-skinned Noughts. The series and its many translations and adaptations — into illustrated versions and twice for stage as well as TV – gets a dedicated section in the exhibit. Alongside correspondence with her editor and feedback on a draft is a newspaper story about the murder of Stephen Lawrence – Blackman was appalled by the handling of the case, which motivated her to write the series.

The books were never intended to be a series, but they became a “response to current events”, Blackman explains in a video accompanying the exhibition. “Double Cross was very much a response to the proliferation of knife crime and joining gangs to feel safe. And then Crossfire and Endgame, the last two novels in the series, were just a response to Brexit and Trump”.

Blackman’s cultural impact is also on display, not only in her children’s laureate medal and Bafta but in snapshots from music videos by Stormzy, who has called Blackman his “childhood hero” and said that Noughts & Crosses is his favourite book. Blackman and her book feature in two of the grime artist’s videos, and he acted in the BBC Noughts & Crosses adaptation. This year, his publishing imprint, #MerkyBooks, published Blackman’s memoir, Just Sayin’.

The author hopes that the exhibition will “encourage, and entertain, and enlighten” visitors. “I never dreamt, when I first started writing, that I’d have an exhibition going on in the British Library,” she says. “It does feel totally surreal”.

• Malorie Blackman: The Power of Stories runs from 24 November 2023 to 25 February 2024. It is free to visit.

• This article was amended on 24 November 2023. An earlier version said that the Acorn BBC Micro computer on display was the one that Malorie Blackman herself had owned, rather than just the same model.