Pub and its front I preserve in centre of London (8)
I believe the answer is:
barbican
'centre of london' is the definition.
(the Barbican Centre in London)
'pub and its front i preserve' is the wordplay.
I cannot really see how this works, but
'pub' could be 'bar' (both are drinking establishments) and 'bar' is located in the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is present in the answer.
'i' could be 'a' and 'a' is present in the answer.
The remaining letters 'bic' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'in' acts as a link.
Can you help me to learn more?
(Other definitions for barbican that I've seen before include "Watchtower - London arts centre" , "London buildings with Arts Centre" , "Fortified gateway" , "Drawbridge defence" , "Defensive tower above fortified city gate" .)