In 1792, Henry Walton Smith and his wife Anna established the business as a news vendor in Little Grosvenor Street, London.  After their deaths, the business — valued in 1812 at £1,280 —(about ~63764 in 2012, adjusted by inflation) was taken over by their youngest son William Henry Smith, and in 1846 the firm became W H Smith & Sonwhen his only son, also William Henry, became a partner. The firm took advantage of the railway boom by opening newsstands on railway stations, starting with Euston in 1848.  In 1850 the firm opened depots in Birmingham, Manchester and Liverpool.  The younger W H Smith used the success of the firm as a springboard into politics, becoming an MP in 1868 and serving as a minister in several Conservative governments.

Info gleaned from Wikipedia