I know that Sam Smiths pubs sell cheap beer, but in the pubs in London that I go to, namely the LYCEUM TAVERN on The Strand and THE CHANDOS near Trafalgar Square, there is increasingly no effort to pour a full pint, especially if you order a pint of Old Brewery Bitter on the hand pumps. I have started making a bit of fun about it by suggesting that I'm English and therefore don't want an "American head" on my beer. Seriously though, these two establishments, the Chandos in particular, are serving "pints" that are about 15 fl. ozs! So it's not quite as cheap as it seems is it?! They are really being quite fraudulent if you ask me. They pull the pint as fast as they can and present you with a swirling foaming pint, and when you have paid your money and it's settled down with a 2-3 cm head on it, it's up to you to get their attention to get it topped up, and the surprise on their faces is ridiculous, as if they have poured the right amount.
I ordered a pint and a half of OBB in The Chandos and was given two "swirling glasses". When the "half pint" had settled, the head was about 4cms high, so I reckon they served about 6 fl ozs at best. I held it up to show the young man just what he had poured me. He came back and said, "All you have to do is ask for a top up". I yelled back at him over the noise level, "You should try pouring a proper glass in the first place and we wouldn't have to bother"!
I'm new to this Forum, but I hope the Sam Smiths management read these pages, and maybe think about a "mystery shopper" visit to your London Pubs because they are routinely serving short measures, at least the Lyceum and Chandos are!