As you may know, I've a bit of history with direct action.
Most notably, Mark Ballard and I got lifted at a GM protest in 1999, along with four others. We were convicted in 2001 (the group pic there is amusing, as is the Ballard/Castro quote), and acquitted on appeal in 2003.
We always knew our colleagues really well, and never saw any of the paranoia that some activist groups get into. Still, there have been a couple of examples recently where that kind of anxiety proved justified, and where corporate interests have infiltrated campaign groups.
Last year Mark Thomas wrote about Martin Hogbin, who worked undercover at the Campaign Against the Arms Trade, on behalf of British Aerospace (Monbiot on the same story). And just yesterday MotherJones uncovered an NRA mole in the American gun control movement. Both had been in place for ten years or so, passing everything from legal advice to campaign strategy out to their handlers.
The media do something similar too: the BBC sent someone into the Climate Camp last year so they could do a tabloid style "OMG DIRECT ACTION!!1!" scare job. It's a shame they don't feel it would be as worthwhile to get undercover with BAA to see what they're planning. Perhaps it's just too much work to get near the board-room, especially when compared to wandering into a public camp.
Still, there's no point getting anxious about it. We ourselves have environmentalists undercover in corporations across the country and embedded in countless government agencies, passing information on and ready for action. You'll see.
That's a tough gig, though. As Leonard Cohen said, "they sentenced me to twenty years of boredom for trying to change the system from within". (youtube)