No end of tough tape needed to fix this mistake (5)

I believe the answer is:

gaffe

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'this mistake' is the definition.
(a gaffe is a mistake or error)

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for gaffe that I've seen before include "Boob" , "Tactless comment" , "Brick (that's dropped)" , "embarrassing error" , "Indiscretion" .)

I've seen this clue in the Sydney Morning Herald.

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