Electrical hazards lead the list: ageing intake equipment and meter cupboards, overloaded sockets and adaptors, damaged leads, and communal installations that have missed inspection. Portable heaters follow close behind, especially where heating is poor and residents improvise. Smoking remains a steady cause, on balconies and in quiet corners of the common parts. Deliberate ignition is a hazard in its own right: unsecured bin stores, open undercrofts and accumulating mail all hand an arsonist opportunity, which is why assessors check what a stranger could reach and light.
Lithium-ion batteries deserve separate mention because they behave as ignition source and concentrated fuel at once. An e-bike or e-scooter battery in thermal runaway produces a fast, hot and toxic fire that resists ordinary extinguishers, and charging in communal areas puts that possibility directly onto the route residents would escape by. Assessors increasingly record where batteries are charged and stored, what the policy says and whether residents have been told.