### Clue: Return to London hospital is indicative of bad relative to a squint (10)
### Answer: STRABISMAL 
 ### Explanation: Definition: relative to a squint
 **Reversal of**(Return to) ST. BARTS(short for St. Bartholomew's Hospital, the oldest in London) + IS + MAL-(the prefix that's indicative of "bad" in compound words, as in "malpractice").
Answer: Adjective from "strabismus"; squint.