London possibly is centre for ambitious moneyman? (10)
I believe the answer is:
capitalist
'moneyman?' is the definition.
(moneyman is a kind of capitalist)
'london possibly is centre for ambitious' is the wordplay.
'london possibly' becomes 'capital' (London is an example).
'centre for' indicates the central letters.
The middle of 'ambitious' is 't'.
'capital'+'is'+'t'='CAPITALIST'
(Other definitions for capitalist that I've seen before include "Profit-driven person" , "investor" , "businessperson, maybe" , "Free enterprise supporter" , "Marx's bourgeois - a static lip (anag)" .)