The City of London is very small, safe (quick look online returns that the crime rate is "73% lower than London and 67% lower than national average"), and very rich, and obviously right in the middle of a top world city. So I am guessing that their police force is well resourced, able to attract "top talent", and not bogged down by anti-social and petty crime.
Yes it is, a friend had their laptop stolen, the police tracked down the offenders within 2 hours and returned the items. What they also don’t tell you is that it’s a dystopian panopticon and runs on a slightly different legal system than the rest of the U.K.
The City Police have a very, small patch and little violent crime, but are geared up to deal with IRA/ISIS-type threats.
Part of this means they have surveillance coverage of virtually the entire areas. It also mean that they can get anywhere very, very quickly.