A better question is which other cities rival London's drinking culture. Moscow? Helsinki? I've never encountered the public spectacles of drunkenness in other Western European countries.
Depends on race. White people in London win hands down. The dark people of London are mostly Muslims and Caribbeans. They don't drink much.
R2, Dublin and Edinburgh might give London a run for its money in drinking, western capital-wise.
How about Tokyo? I've read that heavy drinking is the norm and expectation among businessmen and even office workers. (at least the men) It somehow affirms their group identity, their commitment to each other and the company.
Definitely London, no real contest.
I know some Scottish posters on a sports board and (Glasgow and Edinburgh) and both agree that Glasgow is much rougher.
The heaviest binge drinking I have ever seen was on weekend nights in Osaka. Japanese people don't seem to drink regularly except for binging on weekends. So much puking in the streets.
Saw more fights and less vomiting outside of pubs in London and Dublin. Lots of drunks in Sydney throughout the week. During my one visit to NYC, didn't see a drinking "culture". Visited several venues where fancy drinks cost a week's pay. I think everyone was one one drug or another.
Between NY and London, the Brits win hands down. I'm from NY and have spent a lot of time in London. This isn't even a contest.
My wife can drink any man in NY under the table.
In London people go out for serious drinking almost every night after work. In New York it's once or twice a week.
How and why do the Brits do it?
I work in NYC and London, and my London co-workers seem to binge-drink nearly every night. Some get absolutely wasted 2-3 times a week, like blackout/puke/pull-down-their-pants drunk (often around co-workers), then spend 90% of their day in a hangover state.