Voting for a non-candidate needs to be an option here. That's what I did. I recently saw a meme that indicated voting for the "lesser evil" just re-enforces evil as a legitimate option. Gradually the amount of acceptable evil continues to increase and we wind up with a situation where good is so far out of reach that we have no way back.
Here in the States, though, voting for the best polling 3rd party candidate is a good option because of the regulations guaranteeing federal funding for parties reaching a certain percentage of the vote. If a third party becomes viable the system will skew enough to create better choices.