"E-bikes and e-scooters, which have become London's fastest-growing fire risk, should not be stored on escape routes. If you can't keep them outside or in a shed, they should be put in a room where you can shut a door and contain a fire,” the London Fire Brigade said.
A battery fire:
https://www.standard.co.uk/news/london/pimlico-fire-johnsons-place-ebike-battery-upp-china-london-fire-brigade-b1141133.html