CBI role model apparently giving high spirits to a bit of a tit in Government (5,3)

'cbi role model apparently giving high spirits' is the definition.
I don't know anything about this answer so I cannot judge whether this works.

'bit of a tit in government' is the wordplay.
'bit of' becomes 'pepi' (I am not sure about this - if you are sure you should believe this answer much more).
'a tit' becomes 'pap' ('pap' can be a synonym of 'tit').
'in' means one lot of letters goes inside another.
'government' becomes 'g' (abbreviation for government).
'pepi' enclosing 'pap' is 'peppapi'.
'peppapi'+'g'='PEPPA PIG'

'to a' acts as a link.

Can you help me to learn more?