The Alexander ALX400 was the first low-floor bus body built in the United Kingdom, first appearing in 1997. The first ALX400s were placed on the DAF DB250LF chassis, closely followed by the Dennis Trident. 2000 saw the launch of the Volvo B7TL / ALX400 combination. The ALX400 soon became one of the more popular low-floor double-decks not only in London, but in the UK. The introduction of the Enviro 400 model in 2005 spelt the end of the ALX400, and in 2006 the model was discontinued. A large number of ALX400s were purchased by Arriva, Stagecoach and First, along with smaller orders from the Go-Ahead group.

Utilising a number of superb images and informative captions, David Beddall documents the use of this bus in London.