It's strong material that has my support in Scottish town (4,7)
I believe the answer is:
fort william
'scottish town' is the definition.
(I've seen this before)
'it's strong material that has my support' is the wordplay.
I cannot quite see how this works, but
'strong' could be 'f' (musical symbol for 'forte', 'strong' in Italian) and 'f' is present in the answer.
'material' could be 'twill' (twill is a kind of material) and 'twill' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'in' acts as a link.
Can you help me to learn more?
(Other definitions for fort william that I've seen before include "Highland town" , "Scottish town" .)