It was by a company called T.P.G. who produced "Pure Shetland Wool" for knitting. Presumably, the company was based on Shetland, but there is no address on the leaflet. And I can't guess what "T.P.G." stands for.
It's good to see an authentic Fair Isle pattern from the 1930s (if that is what it is). Here's what the design looks like, very approximately - I've chosen the colours based only on their names in the pattern, so they may be a long way from accurate.
I read the instructions to see if the jumper is to be knitted in the round. It is - but only up to the armholes. Then the back and front are knitted flat. The stitches for the sleeves are picked up around the armholes (after the shoulders have been grafted), and the sleeves are knitted in the round. So - no steeks.
I knew that I had seen other T.P.G.patterns in the collection, and today I found them. The girl's cardigan below is knitted in fawn and dark blue, with peach, white, pale blue, moorit and yellow.
The materials required include a set of four long needles (15 inch), but I'm not sure how they are to be used. The instructions imply that the back and front are knitted flat in one piece up to the armholes, and you begin by casting on 235 stitches onto two size 10 (3.25 mm.) needles. But probably four long needles are needed to knit such a wide piece flat - the instructions don't say. (Now we would use a circular needle.) Again, the back and fronts are knitted separately from the armholes upwards, and the sleeves are knitted in the round, working downwards from the armholes.
Another T.P.G. leaflet is in a different Shetland knitting tradition - it has panels of a pretty lace stitch on a cardigan and jumper. (Click on the image below to enlarge it.)
I found these T.P.G. patterns alongside some other knitting patterns from Shetland. I think these are later - maybe late 1940s?
The leaflets leave no doubt that these are Shetland patterns "Designed in Shetland by Shetland Knitters" - the company is called "Shetland Wools", with an address in Lerwick. Both the lady's jumper and the gent's slipover are knitted flat - back and front separately. Even the sleeves of the jumper are knitted flat, from the cuff upwards - the only knitting in the round is for the yoke. And the ribs around the neck and armholes of the slipover are knitted flat, too, with seams in the rib, under the arms and on the shoulders. (I find that rather shocking). The company must have decided that knitters outside Shetland just couldn't cope with knitting in the round.
It would be nice to know more about these two companies, and in particular what T.P.G. stands for. So if you have any information. please let me know.