London is under an extreme heat warning as forecasters predict a prolonged period of very hot weather in the capital. Multiple reports say temperatures are expected to reach around 35°C, prompting warnings for residents and visitors. The forecast indicates the heatwave is not expected to be short-lived, with predictions suggesting several days of sustained high temperatures. One outlet reports the likelihood of at least seven days or more of unusually hot conditions, while another also highlights the same warning and the prospect of temperatures around the mid-30s. The coverage aligns on the core points: London faces a significant heat episode, temperatures are forecast to peak close to 35°C, and the event is expected to last for multiple days. As with typical heatwave reporting, the warnings are designed to encourage people to take precautions against the risks of extreme heat, including impacts on health and disruption from high temperatures.