Five must leave Barking Advertiser: most depressing (9)
I believe the answer is:
dreariest
'five must leave barking advertiser most' is the definition.
I can't judge whether this definition defines the answer.
'depressing' is the wordplay.
I cannot really understand how this works, but
'depressing' could be 'drear' (I've seen this before) and 'drear' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for dreariest that I've seen before include "Not the most exciting" , "Most tiresome" .)