[Harry Potter] Is there anything in particular stopping me from teleporting behind Voldemort and bashing him with a smelting stick?

Say I can see Voldemort's location via a long range telescope. Can I just apparate behind him and bash him? Does he have any magical spells that preemptively stop physical attacks? Does he have teleblock on so no-one can teleport within 5 meters of him?

I'm not saying this is a great option, but is it an option?