Charming woman under comparatively stupid son's dark control? (6,6)

I believe the answer is:

dimmer switch

'dark control?' is the definition.

'charming woman under comparatively stupid son's' is the wordplay.
'charming woman' becomes 'witch'.
'under' means one lot of letters go next to another.
'comparatively stupid' becomes 'dimmer' ('dim' can be similar in meaning to 'stupid').
'dimmer'+'s'='dimmers'
'witch' put after 'dimmers' is 'DIMMER SWITCH'.

(Another definition for dimmer switch that I've seen is " Device for varying the intensity of a light".)

I've seen this clue in The Independent.

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