Earlier this year, David Aaronovitch appeared on the BBC Radio 3 Arts & Ideas programme to talk about Doris Lessing because, as he put it: “My father’s in The Golden Notebook.”

Sam Aaronovitch was the inspiration for Comrade Bill, the Communist party officer for culture who has a memorable “sardonic” sense of humour. But it isn’t an entirely flattering portrait: Comrade Bill is suspicious of intellectuals and generally uninterested in the culture that is supposed to be his concern.

Sam Aaronovitch with the infant David in 1954. Photograph: courtesy David Aaronovitch/Penguin Random House

“She got bits of him right and she got bits of him wrong,” said Aaronovitch on the programme. “My mother always said, whenever people mentioned Doris Lessing: ‘Oh that liar.’ I think what she meant was that the writer … takes the liberty of assuming that the thing they need the person to be is the thing they are and slaps them down on the page … My mother reacted to it very badly.”

Roland Barthes, and those who believe that biographical context shouldn’t influence our understanding of a text, would perhaps have had stern things to say to Aaronovitch’s mother; as David said, Lessing was just doing what writers do. Even so, it’s easy to understand why Mrs Aaronovitch was so narked.

You can get a taste of this shock of recognition (if not the personal outrage) by delving into Lessing’s archive, which is held at the University of East Anglia in Norwich. Some of it has been opened for public viewing to coincide with the 100th anniversary of Lessing’s birth this month – and it reveals some fascinating correspondences between her real life and her fictional creation.

One of the first things I saw was a picture of an RAF airman, and a series of evocatively old-fashioned airmail envelopes exchanged by Lessing and Coll MacDonald. MacDonald was one of three pilots Lessing knew in Southern Rhodesia in 1944. (The other two were Leonard Smith and John Whitehorn.)

A 1945 letter from Lessing to Coll MacDonald. Photograph: British Archive for Contemporary Writing, University of East Anglia, Doris Lessing Archive/Whitehorn Letters

I’m guessing the mention of three RAF men in Southern Rhodesia is enough for those who have read The Golden Notebook to have that flash of cognisance: MacDonald, Smith and Whitehorn were like Ted, Paul and Jimmy, the young airmen in the Black Notebook sections of the novel. The coincidences of youth, geography and occupation aren’t the only things that jump out of the letters: there are tangled affections, adulteries, earnest political conversations and concerns about “segregation” that might have come direct from the novel. Then there are passages such as this one:

Clancy Sigal in the late 1950s. Photograph: Jane Bown/The Observer

We dance. I have a dim recollection of drinking brandy … and dancing madly all by myself in the middle of the floor at the Ace of Spades the other night, and generally speaking and behaving in a shocking if enjoyable fashion.

Even more striking are the notebooks where Lessing recounts arguments with her leftist American lover Clancy Sigal. These seem to have been dropped almost verbatim into The Golden Notebook in the sections about Anna Wulf and her American lover Saul Green. The Washington Independent Review of Books even accused Lessing of “theft” because she transposed large sections of Sigal’s notebooks into the novel. When he became aware that Lessing was reading them, he began to write false entries to catch her out. And yes, all this also ended up in The Golden Notebook, where Lessing draws a wonderfully absurd conclusion:

The position is reached where each keeps two diaries: one for private use, and locked up; and the second for the other to read. Then one of them makes a slip of the tongue or a mistake and the other accuses him/her of having found the secret diary. A terrible quarrel which drives them apart forever.

Mixed up with all this intensely personal material is some fascinating politics. There are extracts from the files MI5 kept on Lessing because of her communist sympathies. There is Metropolitan police file noting the occupation in her passport as “writer” and detailing how HM Customs has carried out “a discreet search” of her bag and found “nothing of interest to Special Branch”.

Metropolitan police (Special Branch) report from 1954 on Lessing. Photograph: The National Archives

On the other side of the equation are the letters Lessing was exchanging with a “Mr Aplaten” in Moscow. One of hers sympathised with the loss of his “great leader” Stalin. One from him (which must have crossed in the post with Lessing’s) was written on the very day that the mass murderer died: an event that does much to shake up the characters in The Golden Notebook.

To read through such material is to see the foundations of the novel. In October 2007, shortly after her Nobel prize win, Lessing did an event with UEA where she gave typically short shrift to the idea of even discussing The Golden Notebook. “You know we’re reading a 50-year-old book here. That’s a long time ago,” she said. But then she added: “This book, the essential thing about this book is that it has some kind of a charge which comes from the conditions I was writing in.” Small wonder.