The photos and letters belonged to art dealer James Birch, who acquired them from Keeler in the 1990s.
Birch befriended Keeler in 1993 when she asked him to help sell a limited edition print of the iconic Lewis Morley photo of a naked Keeler sitting astride a reversed Arne Jacobsen chair.
A personal archive of photos of Keeler from her childhood, and letters written by her in the early 1960s, is for sale at book dealer Maggs Brothers. They cast Keeler in a different light to her media image back then.
"The letters are heartbreaking in a way, in that they are written by a young woman who was not that sophisticated despite how the media portrayed her at the time," said Ed Maggs of Maggs Brothers.
Meanwhile three photos of Keeler, two of her posing topless, sold at Sworders in December.
The items have come to market as the so-called Profumo Affair has become the subject of a six-part BBC TV series currently showing, called The Trial of Christine Keeler.
Secretary of War John Profumo resigned in 1963 after it emerged he lied to parliament about his affair with Keeler.
Keeler had also been having an affair with Soviet naval attache, Yevgeny Ivanov, at the same time.
The ensuing scandal and security implications of the two liaisons, occurring at the height of the Cold War, helped bring down the Conservative government of the time.
Keeler died in 2017 aged 75.
In December, Sworders sold three unpublished photographs of Keeler, two where she is posing topless, taken circa 1960 by an unknown photographer.
One colour photo of Keeler with her back to the camera fetched £2300 while another, a black and white print, one of three from an original negative, features Keeler face-on with her arms crossed and went for £3000 hammer.
They were sold by Sworders on December 11 at the auctioneer’s London Sale.
The collection at Maggs Brothers, priced £75,000, includes photos of Keeler as a young girl and letters written by her from Holloway Prison, where she was jailed for six months in 1963.
Keeler’s sentence was for committing perjury in a separate case, after admitting she lied about an alleged assault by another lover.
Frances Bacon champion
Birch, a dealer who was an early champion of Frances Bacon and Grayson Perry, owned the James Birch Fine Art Gallery on the King’s Road, Chelsea. He went on to mount the exhibition ‘Christine Keeler: My Life in Pictures’ at London’s Mayor Gallery in 2010.