The gold leaf coated hands of a clock on Cardiff Castle have been stolen by thieves who climbed 150ft (45m) up scaffolding to reach them.
The ornate clock tower and its statues are a distinctive feature
Police will examine CCTV footage to try to identify intruders at the landmark city centre castle, which is undergoing an £8m restoration.
The copper hands, worth about £500, were installed in the 1980s to replace the 1870 originals.
Police do not know if the theft was planned or opportunist.
In June 2004, the seven 9ft statues representing the zodiac which surround the clock face were restored and work is ongoing throughout the castle site.
The theft took place on the evening of Thursday, 5 January.
A spokesman for Cardiff Council said: "We believe that intruders then climbed the scaffolding tower and vandalised the castle clock."
He said that the damage done to the clock would be repaired within a week and that it would not delay the restoration project.
Under wraps: scaffolding surrounds the clock as it has a facelift
"The matter is now in the hands of the police who are carrying out an investigation," he said.
"Fingerprints have been taken from the scene and CCTV footage is being examined," he added.
"Cardiff Castle is a public building and a great part of the city's heritage. The council takes incidents like this very seriously .
"Assuming that the motivation was theft, the action was pure vandalism and these individuals need to be apprehended and dealt with as a mater of urgency to protect the assets of the people of Cardiff."