One who draws a London landmark (5)

I believe the answer is:

tower

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'london landmark' is the definition.
(I've seen this in another clue)

I don't understand the rest of the clue.

(Other definitions for tower that I've seen before include "Monument" , "See 6 Down" , "Tall column" , "Campanile, for example" , "Rear" .)

I've seen this clue in The Globe and Mail.

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