Team leader fitting into cockney table (7)
I believe the answer is:
captain
'team leader' is the definition.
'captain' can be an answer for 'leader' (captain is a kind of leader). I'm not certain of the 'team' bit.
'fitting into cockney table' is the wordplay.
'fitting' becomes 'apt' (I've seen this before).
'into' is an insertion indicator.
'cockney table' becomes 'cain' (I can't explain this - if you can you should give a lot more credence to this answer).
'apt' inserted into 'cain' is 'CAPTAIN'.
Can you help me to learn more?
(Other definitions for captain that I've seen before include "Naval rank" , "One traditionally goes down with a sinking ship" , "US policeman" , "Ship's commander" , "Skipper" .)