Cancel Tyneside opening (6)
I believe the answer is:
negate
'cancel' is the definition.
(I've seen this before)
'tyneside opening' is the wordplay.
'tyneside' becomes 'NE' (region in North East of England).
'opening' becomes 'gate' (a gate is an opening or entrance).
'ne'+'gate'='NEGATE'
(Other definitions for negate that I've seen before include "Deny the truth of" , "Make invalid" , "Render ineffective" , "Disprove or nullify" , "Cancel; invalidate" .)