In 2005 Mark Ballard and I went to a conference at the Chamber Street museum on the topic of peak oil. It was very informative, full of oil industry professionals as well as the renewables crowd, chaired by a BBC journalist and very alarming.
Coming out of one session Mark saw a familiar face in the crowd - the man at the centre of today's media storm, Nick Griffin.
He had a false name and organisation on his badge (the latter was something like "Verity", but not "Veritas", I don't recall exactly), but there's no mistaking him for anyone else, not even any of the "comedy" Nazis from Allo Allo.
If you're ever unsure it's him, the glass eye is the dead giveaway. It is a replacement for the one he claims he lost when he left live ammunition on a bonfire, and it always looks over your shoulder, as if he's awaiting reinforcements.
We made our way over and engaged him in conversation, just because it seems wrong to let a fascist just stand there unchallenged. It was not a polite conversation.
I raised two vile BNP policies, one on deporting non-British born citizens and one on providing guns to all over-18s. Effectively, he'd be telling some British citizens that their parents, also British citizens, have to be sent back to countries they may have not seen for decades, then he'd give the younger generation guns. Did he have other plans to trigger a race war? Cue some bluster and counter-assertion.
He also denied he was a racist, but a breath later said he'd obviously not let his children marry a non-white person. He then went into a massive rant about the evil Americans which I'm not planning to air here, and I ended calling him a revolting fascist.
I'm not proud of this encounter, although I'm glad there was a crowd around us, not least because the boot boy over his shoulder turned out to be a member of Combat 18 with a history of (no, you'll never believe this) racially motivated violence.
I discovered that a smarter environmentalist from the audience had also approached him later. He played dumb and just asked Griffin about his interest in the issue of peak oil.
The answer was telling - the public turn to the right when faced with economic hard times and social dislocation, he said, and the end of the easy oil economy would put him into Downing Street during the 2020s.
The consequences of imminent oil depletion are grave even before you look at the politics of it, and I've done my best with Green colleagues to raise the issue and the need to give a serious response. Preparing for the next oil price spike and the end of cheap energy will require much the same policy shift as is required to tackle climate change, so there's every reason just to get on with it.
Those of us in mainstream parties put a lot of time and effort knocking the neo-nazi BNP, and for understandable reasons. Fine, but it'd be a lot more constructive to work together on zero-carbon energy and coincidentally make Nick Griffin's grim fantasy even more unlikely.