The very latest arrival, for example, on trial as a precaution (4,2,4)
I believe the answer is:
just in case
'as a precaution' is the definition.
(I've seen this in another clue)
'the very latest arrival for example on trial' is the wordplay.
I cannot quite see how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is located in the answer.
'example' could be 'case' (I've seen this in another clue) and 'case' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for just in case that I've seen before include "the judge needs to be" , "In the unlikely event of problems" , "For insurance" , "how one should be when judging suit?" , "as a precaution" .)