It would be expedient to leave the North and shift the last pair but do it quickly (8)
I believe the answer is:
expedite
'expedient to leave the north and shift the last pair but do it quickly' is the definition.
I can't tell whether this definition defines the answer.
'it would' is the wordplay.
I cannot really see how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is present in the answer.
'would' could be 'd' (I've seen this in other clues) and 'd' is found in the answer.
This explanation may well be incorrect...
'be' acts as a link.
Can you help me to learn more?
(Other definitions for expedite that I've seen before include "Push through faster" , "Hurry" , "Speed up progress (of)" , "Cause (something) to happen earlier" , "Hasten, facilitate" .)