Large flag inside hotel the colour of mud (11)
I believe the answer is:
hearthstone
'large flag' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe there's an association between them I don't understand?
'inside hotel the colour of mud' is the wordplay.
'inside' means one lot of letters goes inside another.
'hotel' becomes 'h' (phonetic alphabet).
'the colour of' becomes 'stone' (I can't justify this - if you can you should believe this answer much more).
'mud' becomes 'earth' (I've seen this before).
'h'+'stone'='hstone'
'hstone' enclosing 'earth' is 'HEARTHSTONE'.
Can you help me to learn more?
(Other definitions for hearthstone that I've seen before include "Material forming a fireplace" , "One may be under fire" .)