How safe is safe?

Last weekend I was on my way home and realised due to the Notting Hill Carnival that my usual route would not work.

I instead diverted and took the Hammersmith and City line. When I got on the train I thought there looked to be a lot of police. When I took a full 360 degree sweep of the carriage I realised there were not a lot, but a prodigious pack of police.

The ones I could see I counted... 42

Never before has the tube felt quite so safe.