Note attempt to annul endless external organisations such as the NHS (7)
I believe the answer is:
quangos
'nhs' is the definition.
I know nothing about this answer so I can't judge whether this works.
'note attempt to annul endless external organisations such as' is the wordplay.
I cannot really understand how this works, but
'note' could be 'n' (abbreviation) and 'n' is found in the answer.
'attempt' could be 'go' (go is a kind of attempt) and 'go' is found in the answer.
'as' could be 'qua' (I've seen this in another clue) and 'qua' is found within the answer.
A single letter 's' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'the' acts as a link.
Can you help me to learn more?
(Another definition for quangos that I've seen is " Bodies funded by government".)