I have personally been part of a situation where Police in London have pulled back and retreated to the station rather than call up back up when dealing with a discharging pub for example. They later told me, they are radically down on manpower and often just drive the paddy wagon around with a single officer in the vehicle to just give the impression they are patrolling in force.
Not if its a football game. Then they can forget the law and abuse the human rights of football fans by locking them down, beating them indiscriminately with their batons and generally behaving like hired thugs. Which is what most robo pigs are on the weekend. Strangely enough though, they can't take it. Just like giving it out.
And up north, where I come from, they're scrotes not chavs.