I understand the spitting at someone intentionally in the UK is an act of assault; my question is more in the relation to the acceptable forms of retaliation, whether throwing a punch for example would be deemed as reasonable or whether this would then qualify as an assault itself but on your part. What is the best way for a member of public to respond to this form of assault, being under UK (or EU) law. Any response is greatly appreciated.
You are allowed to respond to a threat with reasonable force
You are not allowed to retaliate.
A past assault does not allow the use of force: an immenant one does.
Technically, someone threatening to spit on you is assault, them actually doing so is battery. Striking someone in response to being spat on is itself battery.