An early to mid-19th century half-pint pewter ale mug or measure in the Georgain taste, and dating from 1820 to 1840.  The mug is a bulbous or pot-bellied tulip form, with a nice un-polished silver-grey colour, sitting on a flared foot and a double scroll handle with thumb-rest. Marked variously for Westminster post 1826 with the portcullis, and "SDL" (SD over L) for Longton Market Company.  Longton was then a market town 4 miles (SE by E) from Newcastle-under-Lyme which together with Lane-End may have exercised
weights and measures functions before the Markets and Fairs Clauses Act, 1847 made it possible for the town market to commence inspection of weights and measures. Other marks include, "IMPERIAL" denoting production after 1826, the Staffordshire County Knot with numbers 69 and 10, a Crown over an indistinct ..IV which is considerd William IV.  There are two further marks that I have been unable to trace - one is an indistinct animal, and the other a chiselled and stylised "L".

So, once you've impressed your fellow drinkers with that lot, you can claim also to be helping the planet.  For this is a eco-friendly, sustainable mug, providing the user with enhanced operational efficiencies and enviro-cred's that accompany the recycled usable piece of history. 

Incorrectly called a tankard, which as you know is a mug with a lid, this purveyor of joy will both delight the casual imbiber, and nurture performance in the serious responsible quaffer.