According to this article, if workers take industrial action over the same problem for more than three months, they can be fired en masse. So as long as a company hangs on, they can behave as badly as they like and get away with it.
It is of course Tory legislation from the 1980s. And, equally inevitably, Blair's New Labour government left it in place. The party founded by the trade unions spent a lot of time boasting to international corporations that the UK has the least workers' protection of any developed country.
Even I'm pretty shocked by this one. Don't fly British Airways. They're total bastards. If you have to, be extra nice to their cabin crew, who behind the smiles are having a tough time. Support Unite's campaign.