I'm a lifetime protester. I know the difference between my " right to protest in a healthy democracy", and deliberate sabotage of lawful events in order to incitement public disorder with a total disregard for safety.
These people are the equivalent of shouting fire in a theatre, skinheads at Gay Pride; Prolifers harrassing patients and staff at abortion clinics, justified as "their right to protest".
On one of the biggest security operations Britain has ever seen, any one stupid enough to openly threaten the occasion, or challenge the police is just inviting arrest.