In oppressive regimes, art is often a lifeline, not a luxury – and political cartoonists the heroes of freedom of speech.  Picture the scene: it’s  2016 and Iran’s Supreme Leader, Ayatollah Khamenei, has issued a fatwa against women cyclists on the grounds that “Riding a bicycle often attracts the attention of men and exposes society to corruption, and thus contravenes women’s chastity, and it must be abandoned.”