Light box to carry on banner (11)

I believe the answer is:

conflagrate

'light' is the definition.
(I know that conflagrate is a type of light)

'box to carry on banner' is the wordplay.
'box' becomes 'crate' (crate is a kind of box).
'to carry' indicates putting letters inside.
'banner' becomes 'flag' (I've seen this in another clue).
'on'+'flag'='onflag'
'crate' going around 'onflag' is 'CONFLAGRATE'.

I've seen this clue in The Telegraph.

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