Key point being the "succesfully" qualifier

Though, as I understood from reading comments here, the UK legal system is so fucked up and medieval that they don't have to win to succeed at their goal.

So much for Magna Carta

It's also true in the US that you can damage someone gravely through a lawsuit that's ultimately unsuccessful. The UK appears to be worse, both through the total absence of anti-SLAPP protections but also because norms that make it more process-bound willing to entertain such a weak case.