The world hasn't just watched on. You've acknowledged that we (those that value democracy) have supplied equipment.
Ukraine are getting powerful kit, we have to stop short of sending in our jets and foot soldiers for obvious reasons.
Putin and his cronies act like they are the only ones who possess nuclear weapons.
Russia could never launch a nuclear attack on a small island such as the UK. We have an 'always at sea' nuclear armed submarine, that at the very least would turn Moscow to dust. That's a price that the Kremlin wouldn't be prepared to pay.