### Clue: Red hot tape turned out to be highly informative porn! (4,6)
### Answer: DEEP THROAT 
 ### Explanation: Definition: highly informative porn!
An anagram ('turned out') of 'red hot tape'. The definition goes back a bit, to 1972: originally it was the title of a pornographic film, then taken up for the informant, originally anonymous, in the Watergate scandal.