It stopped because people don't want to pay the taxes required to have a police presence on the streets.
And when the police actually do their job, and deal with an incident like this one, people will post the footage all over social media accusing them of being racist (wouldn't have done it if they were white), sexist (that officer told that women to calm down), or bullies in uniform (those officers just punched that guy who was trying to stab them).
We either need much tougher laws, with sufficient prison/rehabilitation places to make those laws effective, or we need four times the number of police officers we currently have.
But again, nobody wants the pay the necessary taxes to fund all of that, so round and round we go.
But don't forget, no matter what happens, blame the police. Your MP's job depends on you doing this.