Church leaders in Dublin have said they are "devastated" after the theft in broad daylight of the preserved heart of St Laurence O’Toole, the city’s patron saint.

Thieves entered Christ Church Cathedral early hours on Saturday morning when they made off with the heart which has been preserved in the Cathedral since the 13th century.

Cathedral staff are baffled as to why anyone would want to steal the heart of the former Archbishop of Dublin.

The Irish Times reports that the relic was kept in a wooden heart-shaped container sealed within a small iron-barred cage in St Laud’s chapel in the cathedral. The bars of the cage had been cut.

A spokeswoman said: “The cathedral was opened at 9.30am on Saturday morning and there was no alarm or sign of any break-in.

“The thieves would have needed a metal cutter to prise back the bars that protected the enclosed heart.

“The thieves ignored valuable gold chalices and gold candlesticks in the chapel in favour of the relic. It’s completely bizarre.

“They didn’t touch anything else. They specifically targeted this, they wanted the heart of St Laurence O’Toole.”

Most Reverend Dermot Dunne, the Dean of Christ Church Cathedral and the diocese of Dublin and Glendalough, said: “We are devastated by the theft.

“It has no economic value but it is a priceless treasure that links our present foundation with its founding father, St Laurence O’Toole.”

The theft is the third such robbery in recent months. A holy shrine that normally contains a relic of St Brigid was stolen from a church in north Dublin while three ancient relics were taken from Holycross Abbey, near Thurles, last year but were later returned.

Laurence O’Toole was Archbishop of Dublin when he died in November 1180 in Normandy, France.

The Irish Times describes him as: “An ascetic who wore a hairshirt, never ate meat and fasted every Friday, Each Lent he returned to Glendalough, Co Wicklow where he had previously been abbot. While there, he lived in St Kevin’s Cell, a cave over the Upper Lake, for 40 days.

“He was canonized in 1225 by Pope Honorius III and his heart was preserved in Christ Church Cathedral since the 13th century.

“His skull was brought back to Britain in 1442. His bones were interred at the parish church of Chorley, now called the Church of St Laurence. They disappeared in the Reformation under the rule of Henry VIII.”