Live beer (like Marston’s Pedigree) is always evolving. Allowed to condition naturally to mature as it were, a beer with a little extra yeast to jumpstart the fermentation process again.  Breaking down the sugars to release a greater depth of flavour. The CO2 produced by the yeast can’t escape so it dissolves back into the beer, carbonating it as it goes. This is what makes it look cloudy. But give it a second. Let the sediment settle and then pour it smoothly into a glass.  Cheers.