According to Christopher Breward of the Victoria and Albert Museum the tailed morning coat finally gave up to the lounge suit with the rise of American business culture at the end of the 19th century.

ECONOMIST: Men's clothing

The style and design sensibility that emerged in the years that followed the 1948 Olympics is what curator Christopher Breward calls "a tempered Modernism" a movement distinct from its American and European counterparts mainly in its refusal to completely leave the past behind.

WSJ: British Design at the Victoria & Albert Museum: A Nostalgic Leap Forward