[Steve in Pudsey]

(Whatever your view on the action we should respect his choice, if indeed it was a choice - only NUJ members are entitled to take part. Given that union membership is a protected characteristic, speculation may be unwise.)

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.