It could trigger explosions and a chemical reaction involving chlorine, which can irritate the skin and eyes and affect breathing.

A red alert remains in force, and around 300 residents living in the Tazacorte districts, near the coast - which have been affected by heavy ash fall - have been advised to remain indoors.

https://twitter.com/IEOoceanografia/status/1443106639725436929

Hundreds of homes have been destroyed and around 6,000 people have been evacuated from the area since the eruption on 19 September.

Spanish authorities have declared La Palma a disaster zone, pledging financial support for those affected by the volcanic activity.

A spokesperson for the Scientific Steering Committee said that gas clouds of this kind "dilute rapidly" and the stay indoors measure had been implemented "as a precaution".

The Canarian minister responsible for the region’s Volcano Emergencies Plan, Julio Pérez, said: "We are working as one administration in this crisis."

A no sailing zone has been increased one mile further north and flight cancellations remain in place.