Double-decker bus
The first commercial horse-drawn double-decker omnibuses were introduced in England in 1847 by Adams & Co. of Fairfield, Bow, then improved upon by John Greenwood, who introduced a new double-decker in 1852.
East Lancs 1984-style double-deck body
This design was introduced in 1984. Early examples included Dennis Dominators for Leicester CityBus. At first it was often specified for coach use, sometimes by operators that at the same time specified one of the plainer designs for bus use. This has sometimes earned it the misnomer "coach body", but in fact a majority were double-decker buses.