Northerner races just outside London, missing the start (4)

I believe the answer is:

scot

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'northerner' is the definition.
(someone from Scotland)

I cannot understand how the remainder of the clue works.

(Other definitions for scot that I've seen before include "National" , "---- free: originally free from penalties of taxation" , "one from the North of Britain" , "Someone from north of the border?" , "Jock?" .)

I've seen this clue in The Independent.

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