Large regions of Spain, Portugal, Andorra and parts of France have been crippled by a mass power outage - with telephone and train lines inactive as authorities deal with the chaos.

Spanish power grid operator Red Electrica has said it is working with energy companies to restore power as quickly as possible.

On social media, the firm said that it had invoked "power supply restoration plans in coordination with industry partners following the blackout across the peninsula."

It added: "The causes of the incident are being investigated, and all available resources are being allocated to resolve it as quickly as possible."

Around 20 million British tourists visit Spain and Portugal combined every year.

In the former, hotspots Seville, Barcelona and Valencia have all been affected by the outage.

While in capital Madrid, the underground network has been evacuated, traffic lights are down, and play has been suspended at the Madrid Open tennis tournament.

Its Barajas international airport, which serves around one million passengers daily, was left without power.

In Portugal, official sources have told domestic media that the blackouts are nationwide.