Turnbull & Asser is an English brand, which was established in 1885. It specialises in shirts, but offers various accessories too. Turnbull & Asser socks are made in England of Egyptian cotton (fil d’ecosse) and merino wool. The brand offers mid-calf and over-the-calf socks. Unfortunately, they’re available only in solid colours, but the range of colours is wide: black, grey, navy, blue, red, navy, orange, yellow, chamois, lilac, purple, racing green, dark green, brown, ecru, etc.
Turnbull & Asser socks are available in several sizes: S, M, L, XL. You can purchase these socks at TurnbullandAsser.com. They cost 20-25 GBP (incl. VAT). As far as I know, Turnbull & Asser socks are never put on sales.