The ultimate ancestor of this pattern is the Sewaholic Thurlow, but all that’s really left of it is the fundamental proportions and the crotch curve. These have about four inches added above the waist, no waistband piece, six additional darts, side button closures instead of a front fly, and waist facings with the grain running around the body (essentially an inside-only waistband.) I also shortened them to knee-length.
A note if you want to shorten regular trousers into knee breeches: on full-length trousers, the side seams are partly pulled into line by the shape and weight of the cloth in the lower leg. Cutting them off below the knee means the seams splay out; I needed to take about an inch off the outseam at the knee and maybe another inch out of the front (only) at the inseam to get them to hang straight. A similar alteration would probably be needed on most other trouser patterns or indeed if you were physically shortening existing trousers.
Fabric is a mystery navy twill from the Sue Ryder charity shop in Headingley – Leeds sewing/costuming people, GO; they have amazing vintage clothes and frequently amazing vintage yardage too. From a burn test it’s wool/poly; it responded very well to steam + pressure on thick seams so I reckon there’s a decent amount of wool in there. (My mother doesn’t have a clapper, so I used a long straight piece of Brio #lifehack.) Buttons came from my mum’s stash and ribbon from the Samuel Taylor 3-for-£1 bin.
This was cut and sewn over a long weekend at my parents’ place, with all the machine construction done on Mum’s Elna, praise be to its auto-sizing 1-step buttonhole function – I love my workhorse Brother but I would not want to do 22 buttonholes with it. Six of them are the actual fastening; the other 16 are for the knee lacing, which is non-functional – there’s a facing underneath which is sewn into the hem. I handsewed the buttons and the hem at home.