Regularly torture depressed Palace fan? (4-4)

I believe the answer is:

true-blue

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'palace fan?' is the definition.
The definition suggests a singular noun which matches the answer.

'regularly torture depressed' is the wordplay.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
'depressed' becomes 'blue' (I've seen this before).
The alternating letters of 'torture' are 'true'.
'true'+'blue'='TRUE-BLUE'

Can you help me to learn more?

(Other definitions for true-blue that I've seen before include "staunchly faithful" , "Staunchly loyal (Tory?)" , "Staunchly loyal Conservative" .)

I've seen this clue in The Independent.

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