Seymour Platt said the decision to block an appeal against his mum's 1963 perjury conviction was "a disgrace".
He says the charges against Christine, who died aged 75 in 2017, were cooked up to smear her after her affair with Tory minister John Profumo two years earlier.
And in an exclusive interview, defiant Seymour says he would now seek a government pardon.
Seymour, 53, said: "I won't give up. This is just another step towards justice. We will be making the application soon.
"My mother deserves justice. Everybody deserves justice. What happened to my mother was wrong, she shouldn't have gone to prison." Jazz singer Aloysius "Lucky" Gordon was jailed in June 1963 for assaulting Christine.
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But he successfully appealed his conviction after two witnesses claimed Christine had lied to the court that they were not present at the time of the attack.
Christine admitted perjury in December 1963 and was jailed for nine months.
Seymour's legal team say she was put under pressure by the witnesses and that she lived in fear of Gordon.
But the Criminal Case Review Commission said it was unable to send the case for an appeal.
The CCRC accepted that: "Miss Keeler could not have secured a fair trial, particularly in view of the unprecedented level of prejudicial media coverage of her."
But denying the appeal, it said: "In quashing the perjury conviction, the Court of Appeal would have a very limited ability to correct the public record in relation to Christine Keeler's part in the Profumo Affair.
"The Court of Appeal's role would be focused upon the safety or otherwise or Christine Keeler's conviction for perjury.
"A judgment from the Court of Appeal quashing the perjury conviction would not be able to restore Christine Keeler's reputation or alter her public image."
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The CCRC added: "The quashing of the conviction would be unlikely to reduce the media coverage of the case, in fact the opposite is true." Seymour, who now lives in Longford, Ireland, with wife Lorraine, and their daughter, Daisy, said: "I actually think it's a disgrace, they're basically justifying why they think it's right to deny Christine Keeler justice."
He added: "She was the victim of an assault, it's all there in the public record. She was stalked and assaulted by a man. I'm determined to clear her name.
"In her will after she died, she asked me to tell the truth about her life. She went to prison and she should not have gone to prison." Revealing his plan to ask for a pardon, which would have to be signed by the King, he added: "I promised to clear my mother's name and I will continue, I won't give up.
"We will carry on. We will put in an application to the government and the King and I understand Queen Camilla campaigns to stop violence against women.
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"I think this is an excellent example of a woman who suffered violence by a man and went to prison." Married War Minister Profumo, then 46, slept with Christine when she was just 19 after meeting her at a party.
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