The ineffective soft touch modern approach, of keeping the police out of it if at all possible.
Doesn't work when its hatred between fans.
The police have the training, armoury, protective gear and legal powers to crush offences by weak 19 year old cowards.
Cue "Our marvellous staff worked under unprecedented pressure yesterday evening".
The club had 7 months to plan for such evenings with both CP and the Police, with huge PL cash flows to afford as many police as they deemed necessary.