The claim is the latest in a series of bitter exchanges between Brady and Hindley who last week confirmed she would be hypnotised in an attempt to find the missing body of Keith Bennett, one of their victims.
Brady immediately poured scorn on her proposal earlier this month and said the hypnotism was a publicity stunt in which Hindley would "fake" a trance.
In a statement published in the Independent yesterday, Hindley challenged him to take a truth drug and "tell the truth for the first time in your life".
In retaliation Brady released to the press details of a letter he has written to the Home Secretary. He claims: "At our trial for three murders, all the evidence I gave was designed to save Hindley from imprisonment.
"From our prisons we corresponded for six and a half years. Yet she now claims I forced her to do everything. Even at that early date, Hindley incessantly campaigned for parole."
He writes that in June 1985, he confessed to further murders, including those of Pauline Reade and Keith Bennett.
"During the following 18 months Hindley continued to protest her innocence of all the murders . . . The only murder she could not deny in this manner was that of Lesley Ann Downey, as her voice was taped. Hindley insisted on killing her with her own hands, using a length of silk cord, which she afterwards liked to toy with in public in the secret knowledge of what it had been used for."Reuse content