Don't forget

[timbim]

This would be an absolute necessity if voting were made compulsory in the UK.
It's outrageous enough that it isn't included on ballot papers already.

"None Of The Above!"

You can register an abstention by spoiling your ballot paper.

 

[Grizzly]

Spoiling doesn't really count as an abstention, though.
Too many variables.

http://www.electoralcommission.org....42650/Online-version-102-06-all-documents.pdf

A 'none of the above' option would be far too scary a prospect for our politicians to consider...