Key Facts

• An amber weather warning for extreme heat has been extended by the Met Office, now in force from 01:00 BST on Monday through to 23:59 BST on Thursday, covering large swathes of England and Wales.
• Daytime temperatures are expected to exceed 30C (86F) widely across the warning area, with the hottest locations potentially reaching around 38C (100F), while overnight temperatures are forecast to remain unusually high, with some urban areas struggling to fall below 20 or 21C (68-70F).
• The heat is spreading from continental Europe, where temperatures in parts of western France could climb to 43 or 44C (109-111F) over the next few days, with Paris likely to reach 40C (104F), which would be unprecedented for June.
• The Met Office says adverse health effects are likely to be experienced not only by vulnerable groups but across the wider population, with substantial changes to working practices and daily routines may be required, while heat-sensitive systems and equipment could be affected.
• For a hot spell to officially become a heatwave, temperatures must exceed a threshold - which varies from 25-28C (77-82F) in different parts of the country - for three consecutive days, with the UK Health Security Agency also issuing heat-health alerts across parts of England.