Yes, I'm in the UK. Forget about mob sackings, would not last a second at a tribunal.

But, in the US are there not even civil remedies? Could someone claim 'mob rule' or 'whispering campaign'?

In the US, you have protections if you have a union contract. Otherwise, you pretty much need to be considered a protected class (varies by state), and your sacking was related to your class status.