Local council budgets are being cut. Libraries and swimming pools, after school activities, policing. All being eroded.
From what I see of the news, it's somehow different this time. Perhaps more nihilistic, versus the more confrontational riots in the eighties. It definitely seems there's a goal of hitting shops full of 'shinys'.
Of course, modern messaging may also be playing a part in enabling more 'agile' riots.
Black bloc animals will seize upon any cause, just or otherwise, as an excuse to loot and cause mayhem - and the worst part is, their mere presence erodes the credibility of otherwise legitimate groups with legitimate grievances.
Rome has a similar thing with the Carabinieri, I understand these guys are part of the military.
The City of London police don't especially carry firearms. That said, you may see more of the specially armed police in the City, simply because of a high terrorist threat