Around 4,000 festival-goers were advised to vacate the venue as a precaution. Fire-fighters brought the blaze under control in just over an hour with no victims to report.

Spread over 48 hectares the Andanças dance and music festival in Castelo de Vide in Portalegre expects to welcome some 40,000 visitors by Sunday.

GNR police are investigating the cause of the fire.