Central government will declare a Level 4 alert in the event of severe or prolonged heatwave affecting sectors other than health. Emergency response – continue actions as per Level 3 unless advised to the contrary. Central government will declare a Level 4 alert in the event of severe or prolonged heatwave affecting sectors other than health and if requiring coordinated multi-agency. High-risk groups Community Over 75, female, living on own and isolated, severe physical or mental illness; urban areas, south‑facing top flat; alcohol and/or drug dependency, homeless, babies and young children, multiple medications and over-exertion Care home or hospital Over 75, female, frail, severe physical or mental illness; multiple medications; babies and young children (hospitals). Because Level 2 is based on a prediction, there may be jumps between levels. Following Level 3, wait until temperatures cool to Level 1 before stopping Level 3 actions. A decision to issue a Level 4 alert at national level will be taken in light of a cross-government assessment of the weather conditions, coordinated by the Civil Contingencies Secretariat