Lancashire football team mostly played very fast (6)
I believe the answer is:
presto
'played very fast' is the definition.
(musical direction)
'lancashire football team mostly' is the wordplay.
'lancashire football team' becomes 'Preston' (Preston North End FC).
'mostly' means to remove the last letter (most but not all of the word).
'preston' with its last letter removed is 'PRESTO'.
(Other definitions for presto that I've seen before include "Poster (anag.)" , "hey......,cries the magician" , "rapidly" , "Very fast (mus.)" , "Hey ..., according to the magician" .)