Conservative tone emerging from Ely: 'Labour worried' (5,4)

I believe the answer is:

royal blue

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'conservative tone emerging' is the definition.
I can't tell whether this defines the answer.

'ely labour worried' is the wordplay.
'worried' indicates anagramming the letters.
'ely'+'labour'='elylabour'
'elylabour' is an anagram of 'ROYAL BLUE'.

'from' is the link.

Can you help me to learn more?

(Other definitions for royal blue that I've seen before include "A shade Conservative" , "Queen's shade?" , "Deep rich shade of colour" , "Dark colour" , "(Regal?) colour" .)

I've seen this clue in The Telegraph.

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