Well to be fair Unions have less power than they used to. But it seems more often or not it's a Union that serves the Public sector rather than the Private sector that strikes.
I've been doing some reading on Doctor Who history and it did seem like strikes occurred during the classic era with such monotonous regularity that I'd be surprised if the DW production office didn't factor "strike delay" into schedules and budgeting. And sometimes the strikes occurred for stupid reasons, like the Shada strike apparently was sparked because of a dispute over what union was in charge of a clock or some other prop used on a kids show. So because of that pissing match we lost a Douglas Adams story on Doctor Who.
I'm in Canada so I don't hear about the day-to-day over in the UK. Are unions over there still walking out for silly reasons like that, or are they mostly walking for things that matter like salaries and working conditions? (The strike that shut down DW last week I categorize as reasonable as they were supporting fellow workers that had been let go. I wouldn't call that a silly reason and it was just one day. We'll probably be seeing more of that in the next while as more BBC cuts take hold; the CBC here in Canada is facing similar cuts and I'd be surprised if we didn't see a protest strike or two too).
Alex