[Stuart]

That's not correct. You don't have to be in a Trade Union to take part in official action, whether that be a strike or a work-to-rule. However, it does have to be a recognised Trade Union for the work that you do.

Interesting. There's two recognised unions at my place of work, my union always puts out advice when the other lot are on strike that for us to refuse to cross their picket would be illegal secondary action.

That's not correct of the Trade Union to say that either, although I have witnessed them say it where I work. Either they don't understand the rules or it's deliberate misinformation.

I suppose in many circumstances people just accept what they're told. An employer no longer knows whether or not you're in a Trade Union, never mind which one. Any absence on the day would be recorded by payroll as simply 'Unpaid Absence - Strike Action', or something similar.

In the context of this forum, once a broadcaster knows what resources are available, they may well redeploy accordingly to provide the best cover.