United backed excellent source of funding to achieve ideal state (6)
I believe the answer is:
utopia
'ideal state' is the definition.
(I've seen this before)
'united backed excellent source of funding' is the wordplay.
'united' becomes 'U' (abbreviation as in Man U for Manchester United).
'backed' means one lot of letters go next to another.
'excellent' becomes 'top' (top can mean the best).
'source of funding' becomes 'ia' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'u'+'top'+'ia'='UTOPIA'
'to achieve' is the link.
Can you help me to learn more?
(Other definitions for utopia that I've seen before include "More's perfect society on an imaginary island" , "of limited interest to G&S" , "Idealised place" , "Heaven" , "Thomas More's favourite place" .)