British artist sculpted duke with alarming hat (4,5,6)

'british artist' is the definition.
(British painter)

'sculpted duke with alarming hat' is the wordplay.
'sculpted' indicates anagramming the letters (I've seen this in other clues).
'with' is a charade indicator (letters next to each other).
'alarming'+'hat'='alarminghat'
'duke' put after 'alarminghat' is 'alarminghatduke'.
'alarminghatduke' with letters rearranged gives 'DAME LAURA KNIGHT'.