Answer thus 'Bedfordshire town contains one' (8)
I believe the answer is:
solution
'answer' is the definition.
(synonyms)
'thus bedfordshire town contains one' is the wordplay.
'thus' becomes 'so' (synonyms).
'bedfordshire town' becomes 'Luton' (town in Bedfordshire).
'contains' is an insertion indicator.
'one' becomes 'I' (Roman numeral).
'luton' going around 'i' is 'lution'.
'so'+'lution'='SOLUTION'
(Other definitions for solution that I've seen before include "The answer to a problem" , "Homogeneous mixture" , "Key" , "A mixture of liquids" , "you're currently seeking?" .)