Temperatures are forecast to be between 5C to 10C above seasonal norms, with Spain's Aemet weather agency warning it was "likely that the heatwave lasts long and persists till at least next Sunday".

Thousands of firefighters struggled to put out a dozen wildfires raging in northern Portugal and central Spain through the night and into Wednesday, in the largest wave of blazes in the Iberian Peninsula so far this year after weeks of summer heat.