The standard measure of beer in the United Kingdom. A plurality of pints are often imbibed by hacks after a good old ranting session in ICU Council.
A pint is 20 fluid oz, or around 568ml. Unless served in the Union's bars, in which case it is probably more like 400ml, due to being served a Short Measure.
Disposable skiffs are not legal measures, if you are a pedant you can complain and state that you require your pint to be poured into a legal measure. This may be followed by the barstaff transfering your beer into said legal measure and back into illegal skiff. Sucker.