A local man reportedly set the blaze after walking into the sacristy, spraying it with a flammable liquid and setting fire to the priests' robes stored there.

A group of tourists raised the alarm after flames and smoke started billowing from the sacristy and emergency services rushed to the building. Some 1,500 people had to be evacuated, though only four needed treatment for smoke inhalation.

The sacristy was destroyed in the blaze and the crypt – part of the building completed while Gaudí was still alive – was badly damaged by smoke.