River has met disaster (6)
I believe the answer is:
thames
'river' is the definition.
(English river)
'has met disaster' is the wordplay.
'disaster' is an anagram indicator.
'has'+'met'='hasmet'
'hasmet' is an anagram of 'THAMES'.
(Other definitions for thames that I've seen before include "River at Goring" , "London's river (6)" , "One going to live abroad" , "capital banker" , "The Ma's in London" .)