An ancient decoration at Carlisle Cathedral was damaged by a burglar as he raided the landmark city building.
Dean Higgins, 34, of Howard Place in the city centre, broke the historic wooden panel, which dates back to the 15th Century, on August 9.
The city's magistrate's court was told that Higgins had been spotted on CCTV in the cathedral gift shop.
When the head verger shouted for him to leave he climbed over the ancient wooden decoration causing "irreparable damage".
The court was told it will require expert examination and restoration work to be carried out, which will not be cheap.
Higgins, who appeared in court today, admitted burglary with intent to steal and entering as a trespasses in the cathedral's gift shop.
He was admitted two shop thefts from B&M Bargains.
The court was told Higgins has an "unenviable criminal record" and was only released from prison some weeks ago.
Pam Fee prosecuting told the judge the damage caused to the ancient wood panel is "priceless", and while Higgins was in the gift shop he was seen to have hold of a charity box.
He caused the damage to the fretwork panel by climbing from the shop over the frame.
Rachel Dixon, for Higgins, said he would like to apologise to the head verger and the cathedral for the damage caused.
He will be sentenced at Carlisle Crown Court on September 8.
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