Libby Purves makes some good points here, but includes this clunker:
One of the sternest responsibilities in a democracy is to vote, surely?
Surely not. To vote is to impose one's own preference onto others. Doing this lightly is not at all responsible - quite the opposite.
Instead, the core responsibility is to consider the options carefully before voting. If, after such reflection, you've decided that no party is worthy of your support, where's the irresponsibility in not voting?
Isn't it irresponsible to legitimize a system which thinks "democracy" consists in no more than a choice between very similar managerialists?