A firm is in court charged with providing backing for the band (12)

I believe the answer is:

accompanyist

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'charged with providing backing for the band' is the definition.
I can't judge whether this defines the answer.

'a firm is in court' is the wordplay.
'firm' becomes 'company' (I've seen this in another clue).
'in' is an insertion indicator.
'court' becomes 'ct' (abbreviation used in road names).
'company'+'is'='companyis'
'companyis' placed within 'ct' is 'ccompanyist'.
'a'+'ccompanyist'='ACCOMPANYIST'

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I've seen this clue in The Irish Times.

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