This is a waistcoat — or vest, depending on your outlook on these matters. It is short, fastens with a single button, and has a fixed collar. The thinking with the collar — stopping at the shoulder seam — is that by not running around the back, the jacket worn over the top will be able to sit more flat and cleanly.
Rather than bother with a collar, the engineer jacket has, instead, no collar. It has an open, gently curved front — the sort of setup one sees sometimes on engineer and railroad-type jackets from yesteryear — and a placket panel that runs on both sides.The back of waistcoat is made with cloth different to the front — a worsted wool, springy and strong, and woven with yarn, much like the front, undyed and natural. Being nowhere near as thick as the tweed front means the waistcoat doesn't bulk up the back of the wearer when a jacket or coat is worn atop.
The single button which sits astute, alone, at the front of the waistcoat is a large one, made of horn, and dark in colour and matte in finish.
The button at the front of the vest isn't all alone in fastening duties, in point of fact, because there is, at the back, a belt, emanating from the rear seams. It is fixed down until it reaches the darts running down the back of the body (and which give the waistcoat some shape) and fastens with two brass loops.
There are four pockets at the front, all of them jetted, with pocket-bags stitched through to the front — not that you can easily see with cloth as hairy as this — and all but one covered with flaps whose corners are slightly rounded.
There's a pocket on the inside of the waistcoat, too. It's one of those subtle, sideways ones, which is tucked into the join of the inside-front and inside-back panels. The pocket is lined with slinky satin — as, indeed, is the back panel of the waistcoat, enabling it to be slinked on without a fraction of friction.
Pray you never run into some Herdwick sheep on a dark night in the Lake District. They're a tough, rough breed, see, and the character which sees them endure the wind and rain of Cumbria at 3,000 feet finds its way into this cloth. It's a heavy, coarse, wiry tweed, very much at one with the great outdoors.