Obtained leave to start talks (3)
I believe the answer is:
got
'obtained' is the definition.
('get' can be a synonym of 'obtain')
'leave to start talks' is the wordplay.
'leave' becomes 'go' (to go is to depart or leave).
'to start' suggests taking the first letters.
The initial letter of 'talks' is 't'.
'go'+'t'='GOT'
(Other definitions for got that I've seen before include "Obtained" , "Landed" , "Received; understood" , "Acquired" , "Caught" .)