The Denison smock was worn in WW2 by the British SAS and paratroopers and took its name from Major Denison, the inventor of the camouflage pattern.
Belgian SAS units served with the British and continued to wear the Denison smock after the war. The M56 used a Belgian camouflage pattern.
It was designed to be worn over webbing to prevent snagging during parachute jumps. As a result, it has a roomy fit, especially in the shoulder. It has press-studs on the pockets, a drawstring inside at the waist and buttons to tighten the bellowed cuff.
This jacket is in good condition, with no tears or holes, though there is some fading to the camouflage. The 'tail', a flap which could be pulled up through the legs and secured with press-studs at the front to prevent riding up, has been removed from this jacket.
It fits as a Medium-Large