Britain is set for highs of 34C this week on what could be the hottest June day since records began.
Parts of the South East, London and Wales could reach at least 27C, rising to a possible 34C on Friday, hotter than Portugal, Jamaica, Costa Rica, the Canary Islands and Cyprus.
These areas may see an official heatwave between Wednesday and Saturday, which is when at least three consecutive days have daily maximum temperatures meeting or exceeding the heatwave temperature threshold. The threshold varies by county.