The Hall for Cornwall in Truro was left flooded last night after its main sprinkler system was triggered forcing an evacuation of the building.

The under stage sprinkler system was activated during the first half of The Grapes of Wrath performance.

The audience had to be evacuated and the performance had to be stopped.

Firefighters raced to the venue at 10.22 after alarms sounded in the main theatre.

A Cornwall Fire and Rescue service spokesman said that when crews arrived found the main sprinkler system had been actuated but no fire was found.

She said: “A further appliance was requested for assistance with salvage. Crews used a main pump and a ejector pump to clear 50-100mm of water over a wide area at basement level.

The cause of the alarm is unknown but after investigation,fire has been ruled out.

A Hall for Cornwall spokesman said: “The building was checked thoroughly and it was established that there was no evidence of a fire . However, due the amount of water in the building and a loss of power, the performance could not continue.

“We are very sorry for the disappointment this must have caused. All last night's customers will be contacted today and given the option to re-book to another performance or to have a full refund.

“A full investigation is now under way.”

She said Hall for Cornwall staff worked hard throughout the night to get the system reset and the building dried out and that the venue is back to usual today.

Saturday evening’s performance will take place as scheduled.