London guards desire securing house in part of East London (6)
I believe the answer is:
yeomen
'london guards' is the definition.
'yeomen' can be an answer for 'guards' (I've seen this before). I'm not sure about the 'london' bit.
'desire securing house in part of east london' is the wordplay.
'desire' becomes 'yen' (yen can mean a longing or desire).
'securing' means one lot of letters goes inside another.
'house in part of east london' becomes 'ome' (I can't justify this - if you can you should believe this answer much more).
'yen' enclosing 'ome' is 'YEOMEN'.
Can you help me to learn more?
(Other definitions for yeomen that I've seen before include "Petty officers" , "Ceremonial officers" , "Small farmers (historical)" , "Naval petty-officers in charge of signals" , "Freeholders (hist.)" .)