Drop of tea, we hear, in blue vessel (8)
I believe the answer is:
downturn
'drop of tea' is the definition.
'downturn' can be an answer for 'drop' (I've seen this before). I'm not certain of the 'of tea' bit.
'we hear in blue vessel' is the wordplay.
'we hear' becomes 't' (I can't explain this - if you can you should give a lot more credence to this answer).
'in' means one lot of letters goes inside another.
'blue' becomes 'down' (I've seen this before).
'vessel' becomes 'urn' (urn is a kind of vessel).
'down'+'urn'='downurn'
't' inserted inside 'downurn' is 'DOWNTURN'.
Can you help me to learn more?
(Other definitions for downturn that I've seen before include "Deterioration" , "Decline in business" , "Worsening of economic activity" , "Decline eg of economic activity" , "Reduction in business" .)