A stickler for hard work, Mrs Keats sits fulminating (12)

I believe the answer is:

taskmistress

'a stickler for hard work' is the definition.
(someone who makes people work hard)

'mrs keats sits fulminating' is the wordplay.
'fulminating' indicates anagramming the letters.
'mrs'+'keats'+'sits'='mrskeatssits'
'mrskeatssits' is an anagram of 'TASKMISTRESS'.

(Another definition for taskmistress that I've seen is " She imposes a heavy workload".)

I've seen this clue in The Times.

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