It’s the standard cry of flacks for the larger and more tarnished parties. Every time a secret dining club with the PM is revealed, every time a millionaire donor turns out to have come by his money through fraud, every time a PM is questioned over cash for peerages, every time a half a million pounds arrives just before policies the donor doesn’t like are dropped.

And of course it’s not true.

Every recent party of government is at it or has been at it or looks like they’ve been at it, but those of us who work for or volunteer for shoe-string operation parties like the Greens get seriously tired of hearing we’re just as bad. Tired as in, in my case, a strong desire to throw the radio out of the window. It suits the corrupted class to swirl their hands in the sewage floating up around their midriffs and pretend that all parties are in just as deep. If all politics is equally corrupt, they imply, why stop voting for us just because we are? No-one else is any better. We’re all in the sewer together.

Seriously, it’s not true.

Sure, Greens have had larger donations in the past, although I can’t remember anything above £20k. Sure, I hoped we’d find a rich donor in good time before the 2011 election to compete with the Soutar warchest and the unions’ money and all the rest. Perhaps we just haven’t had a chance to be corrupted yet. But I don’t think so.

So what can be done about this party funding mess? Leave it as it is and hope the fear of being caught will reduce the likelihood of it being repeated? The evidence is against that. Soutar gave the same amount of money again to the SNP last year despite the 2007 outcry over their abandonment of bus re-regulation, which remains comfortably abandoned. Neither Blair nor any of his associates ever faced trial over cash for honours. The Lib Dems never even gave Brown’s donation back to the people he’d defrauded it from (I regard this as the most egregious on this list, incidentally).

The current wrangle over donations founders on two things. First, parity – will the Tories take enough from Labour through capping union donations or fragmenting them and, conversely, will Labour block enough of the funnel that leads from big business to the Tories?

The “fairness” battle between Labour and the Tories is an odd one, but pragmatically I accept they both need to be happy with the outcome. Personally I’d ban all collective donations to political parties – corporations and unions (collectively) unbalance politics with large donations and are in that way undemocratic, although unions’ other activities remain vital. So by all means make it easy for individual Labour-supporting trade unionists to give to their party, or indeed trade unionists who support any other party to give as they wish. Similarly, individual shareholders are people too, and if they want to give to the Tories or to any other party, fine, so be it.

Second, what about state funding? The public won’t wear state funding, we’re told, although the return on investment would be substantial if the quid pro quid was a system capable of ending the money-go-round. And the large parties won’t wear living on the small and capped donations of their members. So where else could the money come from for state funding?

Well, here’s a crazy interim idea. Donations. Eh? What? Here’s the idea. Take 50% of every donation to every political party and redistribute it according to the votes cast at the last election (or a rolling average across types of election). A hypothecated tax, if you will. A big donor would know that his or her preferred party will benefit most from their donation, but their donation would also be supporting fair funding for other parties too. Yes, it’s crazy. Other suggestions welcome. We can’t go on like this.