They broke the rules governing a strike ballot of union members.
Now it doesn't matter what way you cut the cake Kevin, if an argument or a decision is based on a faulty premise, then the whole thing should fail.

There are 12,700 members of the relevant section of the union. 80 per cent of them voted - that's about about 10,260. And 92 per cent of those voted for a strike - that about 9,400.

Apparently 900 of those voting had agreed to take voluntary redundancy by the time the vote was taken. Still employed by BA, but working out their notice. That means that even if every one of these voted for strike action, and that vote doesn't count, there were 8,500 legitimate votes for the strike, and only about 1,000 against.

Of course for all anyone knows it might be that the votes against the strike were in fact mostly people who had taken redundancy and shouldn't have been voting in the first place.

However you cut the cake, an overwhelming vote was overturned by a court looking for a loophole. British Guided Democracy rules OK...