Opening time to be put back across country, Tory leader admitted (8)

I believe the answer is:
aperture
'opening time' is the definition.
'aperture' can be an answer for 'opening' (I've seen this before). I'm not certain of the 'time' bit.
'be put back across country tory leader admitted' is the wordplay.
'be' becomes 'are' (I've seen this in another clue).
'put' becomes 'per'.
'back across country tory leader' becomes 'tu' (I can't explain this - if you can you should give a lot more credence to this answer).
'admitted' indicates putting letters inside (inserted letters are let in or admitted).
'per'+'tu'='pertu'
'are' enclosing 'pertu' is 'APERTURE'.
'to' is the link.
Can you help me to learn more?
(Other definitions for aperture that I've seen before include "'Hole, opening (8)'" , "Opening, to let light enter a camera perhaps" , "Crack" , "Device controlling amount of light admitted" , "Eye" .)
