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.
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.
The UK "loser pays" model seems like it would be a benefit, but since the norm that they only pay 70% and that your share can be diminished by presenting a comprehensive case (diminished by every argument you lose) the incentives are complicated and its far from clear to me that it doesn't make it worse.
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