Spanish authorities have allowed thousands of people evacuated because of wildfires to return to their homes after restrictions were lifted in the areas of Toledo, Madrid, Ávila, and Castellón.

In the Madrid region alone, 24,000 people have been told they can return and lockdowns on another 20,000 have been lifted.

Spain and France are both braced for the start of the fourth heatwave so far this summer and some fires have continued to burn, including one at Burgohondo 150km (93 miles) west of Madrid.

In south-west France, the largest fires in the Gironde region are described as “still stabilised” despite several flare-ups, however officials warn of dry winds and temperatures of up to 41C (106F).

The mayor of Le Barp, south-west of Bordeaux, Blandine Sarrazin, warned that the situation was “getting harder”, after two fires had broken out the day before, and said everyone had to be “hyper-vigilant”.

Flare-ups were also reported not far from Lanton on the eastern shore of the Bay of Arcachon.

Gironde and the Landes are among 16 departments or districts are under orange heatwave alert.

The fire service has had to deploy special measures in Gironde to protect a number of sites linked to France’s defence and aerospace industries. The so-called “Seveso” sites include plants that manufacture hazardous materials for missiles and rockets.