Alan Turing? Sara Turing? Stuart Russell? Apocryphal?

Question for Quote Investigator: A pioneering mathematician and computer researcher in the 1950s believed that an intelligent computer system could be built, and “it would not take long to outstrip our feeble powers”. Would you please tell me the name of this person and help me to find a citation?
Reply from Quote Investigator: Alan M. Turing was a major figure in the field of computer science who died in 1954. His mother Sara published a book about his life in 1959, and she included a draft of a lecture he delivered in Manchester, England in 1951. Turing’s address titled “Intelligent Machinery, A Heretical Theory” explored the consequences of building computer systems capable of displaying intelligence. Boldface added to excerpts by QI:1
There would be plenty to do in trying, say, to keep one’s intelligence up to the standard set by the machines, for it seems probable that once the machine thinking method had started, it would not take long to outstrip our feeble powers. There would be no question of the machines dying, and they would be able to converse with each other to sharpen their wits. At some stage therefore we should have to expect the machines to take control, in the way that is mentioned in Samuel Butler’s Erewhon.
Below are additional selected citations in chronological order.
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