Answers in the comments, please...
UPDATE: my favourites, both from the comments here and on the forums...
- Three bright colours. Three big parties. One political monopoly.
- Tax and spend! Tax and spend!
- Green taxes! Proceeds of growth! Evil terrorists!
[subtitle: Birds of a feather...]
- Your life! Our choice!
(replace health with "education" or "health" or whatever)
- Nailed to their perch? Dead parties—dead policies.
- Investment before tax cuts or We'll spend more on the NHS than the other guys or Choice in education
- No need for new political parties, squawk!"
[subtitle: We beg to differ...]
- Manifesto pledges are not subject to legitimate expectation!
- This'll hurt you more than it hurts us
- You Pay; We Squander
- [leave the speech bubble blank and then subtitle: Making noise but saying nothing...]
- What did that green parrot over there say we should tax next?
- [subtitle: Birds of a feather fuck you together.]
All good stuff: keep 'em coming!
UPDATE 2: I love this first one particularly...
- The United Colours Of Europhilia.
- Red is for the colour of the Innocents who die in our Hospitals.
Yellow is for the colour of our cowardice at the Referendum debate.
Blue is for the colour of the shallow puddle that divides us from the Rest