One of the things that I find so funny here is how different the view of alcohol is. In British culture pubs are social hang outs. I realize that in a place that is soggy and gray most of the year having somewhere to hang out indoors is required so pubs became the part of the culture to serve that purpose. They have choir practice at the local pub along with their own football team that play against other pub football teams. (Pub culture does have some weird side effects. While shopping I witnessed some kids excited about this year's model of darts just arriving.) As opposed to American bars where people either go to drink or pick up people. So I've tagged along since there is always something to do besides drinking.
As for the school, for starters, there are multiple pubs on campus. One in the student union and one just for post-grads and professors. There are school sanctioned pub crawls for club activities and at the student village I live in. For a few of the big parties thrown at the student village they supply the alcohol. I have never seen any of these things at schools in the U.S. There does not appear to be a worse rate of alcoholism either but I have not been around the undergraduate housing on a weekend. (When living in Oregon, we referred to the street separating student housing from the liquor stores as "drunk alley".)
One of the funny things at the store I've found are 2 and 3 liter bottles of hard cider. It really makes a "40" look puny. (and yes, it is 5% alcohol so similar to beer) Apparently they are the drink of choice for alcoholics and under-age drinking because it costs about £1 a liter. Also when I told them that I used Guinness to cook corned beef on St. Patricks day they said that is all Guinness is good for in America. Apparently it does not ship well, so even the Guinness here in London isn't at it's best. For that you have to go to Dublin. I have not told any of them that I have toured the Guinness factory and did not drink while there. I don't think that would be considered a passable offense.
As far as hanging out with all the different nationalities, everyone says a different nationality can drink you under the table. Be it German, Irish, English, French (as long as it's wine) they all individually admit they are not good at holding their liquor but "such and such" nationality can.
The largest pub crawl is using the tube. Every stop on the circle line you go to a pub. However trying to drink 27 pints in the time from the pubs open to when the tube closes is not an easy task. It is one of those fabled activities that everyone knows about, but no one knows of someone that has accomplished it.