The word used is "pint" but that very often actually means 500ml - there is no weights and measures here so no guarantees of what you will get.
The locally brewed beer (generic gnat's pee lager branded as Carlsberg, Heineken, Stella, etc) is the primary draft beer and is foul for anyone who drinks real beer in the UK. Bottle beers are widely available. Prices for a bottle range from $18 (about GBP1.50) in happy hour through $70+ in posy places where people have more money than sense. Prices for a pint/500ml range from about $25 in happy hour to $75 or more for thinks like Guinness (often badly stored, badly poured and always served far too cold). Most, but not all, places charge you 10% for service, even if you order the beer yourself at the bar. There are a few places which have quite good selections of British bottle beers (e.g. The Globe on Hollywood) and a few that have quite a range of Belgian Beers (e.g. Jubilee in Central) but the Belgian beers are expensive.
The drinking goes on all the time. There are 24 hour bars which pull the shutters down to keep the dawn out and I often walk past them with the music still pumping on my way to work.
Personally I tend to drink wine more than beer these days, but if I am on beer it's most likely bottled London Pride.