British swimmer consumes cold, cured meat in sauce (8)
I believe the answer is:
bechamel
'sauce' is the definition.
(bechamel is a kind of sauce)
'british swimmer consumes cold cured meat' is the wordplay.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'swimmer' becomes 'eel' (eel is a kind of aquatic vertebrate).
'consumes' indicates putting letters inside.
'cold' becomes 'c' (eg on taps).
'cured meat' becomes 'ham' (I've seen this before).
'c'+'ham'='cham'
'eel' enclosing 'cham' is 'echamel'.
'b'+'echamel'='BECHAMEL'
'in' is the link.
(Other definitions for bechamel that I've seen before include "White 7" , "Mix of milk, butter and flour" , "milky sauce!" , "Milk thickened with a butter and flour roux" , "Thick white sauce" .)