Based on its Alexander Dennis Enviro400 City body, which was launched in 2015 to compete with the hybrid electric New Routemaster, the Enviro400EV is produced at Alexander Dennis' Falkirk and Scarborough factories in the United Kingdom, with production of the type at the company's Larbert headquarters set to also commence in mid-2023.

It is the second battery electric bus model from Alexander Dennis, following 2016's launch of the single deck Enviro200EV, also produced in partnership with BYD.

The Enviro400FCEV can be equipped with either a 45 kW or 60 kW Ballard FCmove-HD hydrogen cell as well as a 30 kWh electric reserve battery from Impact Clean Power Technologies, and the Enviro400FCEV has a maximum power output of 350 kWh provided by the Voith Electrical Drive System, offering a maximum range of 300 miles (480 km).

[8] A second-generation Enviro400EV, featuring a newly restyled exterior and driver's cab, a new Voith driveline with a 410 kW peak power output, as well as options for either 472kWh or 354kWh NMC batteries repositioned further towards the front of the bus, was announced by Alexander Dennis in November 2022,[9] with the first complete bus unveiled in November 2023.

An open top variant was also announced upon the launch of the second-generation Enviro400EV,[10][11] while a variant built to TfL specification, offered with 14 year or 1 million kilometres (620,000 mi) warranty that allowed the buses to be used for two consecutive TfL bus contracts without requiring battery replacement, was revealed in August 2024.

Ten of Stagecoach London's Enviro400EVs were used to shuttle delegates and world leaders at the 2021 United Nations Climate Change Conference in Glasgow prior to entering London service,[16][17][18] while a batch of Abellio Enviro400EVs operating on route 63 were delivered with enhanced interiors specified under TfL's Future Bus project.