The Whip, which opened at Drury Lane in 1909, was one of a succession of 'sensation' dramas in which special effects became the principal attraction. The scene in the stables at the beginning of Act III was designed by Bruce 'Sensation' Smith. He was responsible for some remarkable stage effects, famously the onstage train crash at the end of Act III of The Whip, but he could also create beautiful stage pictures, full of detail, as these bustling stables show.
Smith's other sensational spectacles included dramatic scenes in the 1913 show Sealed Orders. This featured an airship from which two villains locked in mortal combat fall to their deaths leaving their hostage, the heroine, on board. The airship is shot down and the heroine rescued from the sea.
To us, used as we are to cinema spectacle, this doesn't sound particularly remarkable, but if you consider that it was all done within the confines of a theatre, you begin to see how Smith got his nickname.