Parent carries you across the Channel, in fact (5)
I believe the answer is:
datum
'channel in fact' is the definition.
'datum' can be an answer for 'fact' (singular form of 'data'). I'm unsure of the 'channel in' bit.
'parent carries you across the' is the wordplay.
'parent' becomes 'dam' (term for the female parent of an animal).
'carries' is an insertion indicator (inserted letters carried inside).
'you' becomes 'u' (commonly used in online communication).
'across' indicates putting letters inside.
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'dam' going around 'u' is 'daum'.
'daum' enclosing 't' is 'DATUM'.
Can you help me to learn more?
(Other definitions for datum that I've seen before include "Premiss, thing taken for granted" , "One item of information" , "Given point or position" , "Minimal information" , "given to the Romans" .)