Increased current cost of Glastonbury venue? (7)
I believe the answer is:
torrent
'increased current' is the definition.
(a fast-moving current)
'cost of glastonbury venue?' is the wordplay.
I cannot quite understand how this works, but
'cost' could be 'rent' (rent is a kind of cost) and 'rent' is present in the answer.
'of' could be 'o' and 'o' is located in the answer.
This may be the basis of clue (or it may be nonsense).
(Other definitions for torrent that I've seen before include "Great stream" , "Overwhelming outpouring" , "Stream in spate" , "Fast-moving stream" , "Swift or violent stream" .)