I have posted a lot of images in a lighthearted manner in this thread, perhaps without really answering the basic question. So let me add a couple of comments.
Firstly, the last time that "street" fashions in Britain were really sharp
was at the time of the original skinheads in 1969 - the Tonik suit, brogues, Ben Sherman shirts, Crombies and sheepskins, Prince of Wales check, Harrington jackets...
Possibly the most quintessentially English designs for men have been the ones I am linking to below. Firstly the Norfolk Jacket. It had a minor revival in the 1960s mod era, and the high street tried to reintroduce it in the 90s with no success, but it is an absolute classic.
The Belstaff Trialmaster waxed jacket for motorcycling led a style which was so much associated with the UK that it was known in America as the "English Jacket".