What was a knifeboard?

The London bus of the 1880s, drawn by two horses, was nicknamed ‘knifeboard’. Those adventurous passengers, usually agile and male, who climbed to its top deck had to sit back-to-back on a long narrow board. The accommodation was rough and some wag soon named the bus ‘the knifeboard’ after the rough emery boards on which cutlery was cleaned until the invention of stainless steel. The knifeboard was one of the first of the double deckers. ‘Garden’ seats, or transverse seats, each seating two, were introduced in 1881.