Pole gives attack dog the slip and joins two Italians who escaped long ago (5,7)
I believe the answer is:
harry houdini
'pole gives attack dog the slip and joins two italians' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.
'who escaped long ago' is the wordplay.
I cannot really understand how this works, but
'who escaped' could be 'houdini' (Harry Houdini was an escapologist) and 'houdini' is present in the answer.
The remaining letters 'harry' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for harry houdini that I've seen is " He could always get free".)