Urgent demands ultimately introducing temporary accommodation providing housing for free (8)
I believe the answer is:
strident
'urgent' is the definition.
(I've seen this before)
'demands ultimately introducing temporary accommodation providing housing for free' is the wordplay.
'ultimately' says to take the final letters.
'introducing' says to put letters next to each other.
'temporary accommodation' becomes 'tent' (I've seen this before).
'providing housing for' means one lot of letters goes inside another (some letters house other letters within them).
'free' becomes 'rid' ('rid' can be a synonym of 'free'**).
The final letter of 'demands' is 's'.
'tent' placed around 'rid' is 'trident'.
's'+'trident'='STRIDENT'
(Other definitions for strident that I've seen before include "Unpleasantly loud and harsh" , "ear-piercing" , "Grating - urgent" , "Harsh, grating" , "harsh sound" .)