A composer possessed focus from day one (5)

I believe the answer is:

satie

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'a composer' is the definition.
(French composer Erik Satie)

'possessed focus from day one' is the wordplay.
'possessed' becomes 'insane' (similar in meaning).
'focus' indicates the central letters (focus can mean the centre of something).
'from day one' becomes 'tie' (I can't justify this - if you can you should believe this answer much more).
The middle letters of 'insane' are 'sa'.
'sa'+'tie'='SATIE'

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(Other definitions for satie that I've seen before include "French avant-garde composer, Erik, d. 1925" , "French composer of the Gymnopedies, d. 1925" , "creative Frenchman" , "Erik -----, French early minimalist composer" , "scorer" .)

I've seen this clue in The Daily Express.

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