To be honest I don't think the injunction does make the strike illegal. An injunction is granted on the balance of probabilities - so the judge thinks it is likely that the ballot was improperly conducted - but a full trial would be needed to decide the issue. To be sure, given that the injunction was granted (but it might be overturned) I think BA would have a good chance of winning such a trial (although that "good" chance would be reduced if Unite win on appeal) - and then I understand the strikers could be exposed as having taken part in illegal action.
Personally though I doubt BA will actually take this course of action. But they might threaten it to prevent any further strike action or ballots. To be honest, unless Unite do get the appeal and win it, this dispute is over and BASSA are finished. The protected period runs out after 12th June and, even if there is a new ballot on the same issue, as far as I am aware this won't be extended. So even with another legal ballot strikers could still be dismissed after that date anyway.
These are the facts, so everyone should digest this before pontificating on what might happen next.
Maybe one of the reasons the union is chasing hard for an appeal is because their lawyers have pointed out just how much trouble they will be in otherwise.
However, i share this opinion. If UNITE are busted now, or after the appeal, they'll lose all credibility to run a strike and more and more employers will run up against them. And more and more employees will wonder exactly what they pay their £xxx/year subscription. I think UNITE are now in a very precarious position.
I can't see the CoA overturning the decision - the precident has been set in the metrobus case last year and to overturn this decision would affectiely mean a law change. This is likely to have to go to the supreme court to do. Will UNITE go that far ? Can they afford to ? Can they afford not to ?