### Clue: Changing allegiance of codebreaker without name (7)
### Answer: TURNING 
 ### Explanation: Definition: Changing allegiance of
 TURING(Alan, considered the father of computer science, and who, during WW2 was a codebreaker in Britain's Bletchley Park) **containing**(without;outside of) N(abbrev. for "name").
Defn: … eg. spies.
Quote:  "… The lady's not for turning", referring to herself.  A re-working of the title of Christopher Fry's play "The Lady's Not For Burning", an ironic reference to what many would have liked to do instead.