Alexander Dennis Enviro400

The Alexander Dennis Enviro400 is a double-decker low-floor bus built by Alexander Dennis. There have been three generations since 2005.
First generation (2005–2010).
The Enviro400 was built in 2005, The chassis could be built on the East Lancs Myllennium Lolyne, Optare Olympus and Scania N-series (N230UD and N280UD) bodies.
One Enviro400 was built on the Volvo B7TL chassis before Volvo B7TL was replaced by the Volvo B9TL, on which more examples of the Enviro400 were bodied.
Second generation (2008–2018).
The second generation Enviro400 was launched in 2008. It had white LED daytime running lights underneath the headlights at the front, new front bumpers and the emergency exit door was in a different place.
Third generation (2014–present).
The third generation Enviro400 (known as the Enviro400 MMC) was launched in May 2014.
It had new front and rear lights, new front and rear bumpers, new windscreen and a new interior.
E400H.
A diesel-electric hybrid version, called the Enviro400H, was launched in October 2015.
E400H City.
A hybrid version, called the Enviro400H City, was launched in October 2015. It is aimed at the London market, and is visually similar to the New Routemaster and Enviro200 MMC. The Enviro400H City is only sold as a hybrid in London to compete with the New Routemaster.