Makeover of cruel TV channel under way (7)

I believe the answer is:

culvert

I'm a little stuck... Click here to teach me more about this clue!

'way' is the definition.
(culvert is a kind of way)

'makeover of cruel tv channel under' is the wordplay.
'cruel tv' anagrams to 'CULVERT'.
But, I'm not sure how the anagram is indicated.

Can you help me to learn more?

(Other definitions for culvert that I've seen before include "Conduit" , "Enclosed drain under a road or railway" , "Tunnel for flow under a road/railway" , "Drain channel" , "Water channel" .)

I've seen this clue in The Telegraph.

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