Suitable leaders of children's holiday activities go after Conservative - it proves humanity (7)
I believe the answer is:
captcha
'it proves humanity' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'suitable leaders of children's holiday activities go after conservative' is the wordplay.
'suitable' becomes 'apt' (I've seen this before).
'leaders of' suggests taking the first letters.
'go after' says to put letters next to each other.
'conservative' becomes 'c' (abbreviation commonly used in UK politics).
The first letters of 'childrens holiday activities' is 'cha'.
'apt'+'cha'='aptcha'
'aptcha' put after 'c' is 'CAPTCHA'.
Can you help me to learn more?
(Another definition for captcha that I've seen is " E-security feature".)