Marston's Oyster Stout

Marston's Brewery has been brewing at Burton Upon Trent, England, since 1834. It proclaims itself as the Official Ale of England, but I don't know if this title is self-imposed or not. This 4.5% stout is a traditional English style brewed using oyster shells. Who first thought that would be a good idea? 

The beer pours extremely dark brown, appearance of black, ruby tint if held to the light. There is nearly an inch of cappuccino light brown, creamy, foamy head. The aroma is dark roasted, toasted malt, a hint of smoke and star anise, a bit of dark cocoa and dark fruits. The taste is lightly sweet and fruity, dark roasted malt, bits of dark chocolate and some coffee. It has a nice amount of carbonation, it is moderately bitter and the finish is dry. This is a very drinkable stout.