When I worked in a pub when I was at college we had 3 sizes for "postmix" soft drinks (i.e. The ones from a dispenser gun not individually bottled). These were "dash" for use with spirits or in a lager top etc,  "regular" which was a half pint glass,  and "pint". The pub I worked at was a free house, so was independently owned and could serve what they liked. In my local now they don't do half pint glasses of pop- it's the large 33cl branded glasses or it's a pint. Those glasses will keep getting bigger. I really hate pubs since your choices are basically booze (which will make you obese in two ways! Once with empty calories and again by keeping your liver busy so it can't process the other junk you're guzzling) , fizzy beetus pop,  or bottled fruit drinks like j2o which you can feel rotting the enamel off your teeth as you drink it.