1930: Grown-ups fretted over grown-up issues like political instability and job insecurity, but for 13-year-old Roald Dahl, 1930 marked the start of the “great golden years of the chocolate revolution”. The limited chocolate choice of the 1920s was suddenly transformed; “the entire world of chocolate was turned upside-down in the space of seven glorious years, between 1930 and 1937”.
The Mars bar first appeared in 1932; Chocolate Crisp was launched in 1935 and renamed Kit Kat two years later; Aero also went on sale in 1935; Quality Street made its debut in 1936; and Maltesers, Rolo and Smarties were introduced in 1937.
Source: Felicity and Roald Dahl, Roald Dahl’s Cookbook (1991), pp. 150–5