Anna Rowe

If one was knocked down by a runaway police horse, one would have an actionable case against the police.

Thanks for that. I assumed that everyone has a duty of care at all times towards everyone and everything.

Not always but that case clarified that when police are enforcing the law they DO owe a duty to others - The person trampled by the horse will be entitled to damages

Which in reality should then be recouped from the brainless idiot that threw the firework.

Indeed but it was foreseeable that a horse can get 'spooked' and can react unpredictably even if trained to overcome their natural fears - eg Police dogs often bite the wrong person - usually just the person who gets too close to their jaws - I should know I was bitten in 1994

I agree to some degree but here the protester purposefully threw the firework at the horse just like the bikes were pushed/thrown at the horse. Not the same as a bang somewhere scaring it.

The police are still engaged in law enforcement so whatever flows from that, including a bolting horse (for whatever reason), places them at risk of being sued for any injuries caused by them (or their equipment) to those present in the area -No different to a police car pursuit