### Clue: Decline of London area on city border (7)
### Answer: ECLIPSE 
 ### Explanation: Definition: Decline
 SE(abbrev. for "southeast", postal code of the London area, or the area of England where London is) **placed after**(on, in an across clue) [ EC(the postcode area containing almost all of the City of London) LIP(a border;a rim) ] .
Answer: A fall into obscurity or disuse, as in "many pop groups go into eclipse after a brief period of fame".