To go back to your question, hammerman, it seems he has been arrested on suspicion of violent disorder and criminal damage (to the flag).
If the charge is maintained, Violent Disorder is the most serious of the Public Order Offences and usually results in a custodial sentence handed down by the Crown Court. Magistrates' sentencing guidelines suggest that only in rare cases (those involving minor violence or threats of violence leading to no or minor injury, with few people involved and where no weapon or missiles are used) may a custodial sentence within the jurisdiction of a magistrates’ court be appropriate.