"...Police outgunned by better weapons..." Hard not to be outgunned when you don't have a firearm to start with. That'd be a story in England, but wouldn't even make the papers in North America. There would be no records of such an event, Stateside.
Winston carried a C96 at Omdurman in 1898, so a gun fight in 1911 London(lots of semi-auto pistols around by then) wouldn't have been one of the first engagements.