When was the first instance of vandalism inflicted on the statue of the "Little Mermaid" at Copenhagen?

The Little Mermaid is a bronze statue by Edvard Eriksen, depicting a mermaid becoming human. The sculpture is displayed on a rock by the waterside at the Langelinie promenade in Copenhagen, Denmark. Based on the 1837 fairy tale of the same name by Danish author Hans Christian Andersen, the small and unimposing statue is a Copenhagen icon and has been a major tourist attraction since its unveiling in 1913. In recent decades it has become a popular target for defacement by vandals and political activists.

The statue has been damaged and defaced many times since the mid-1960s for various reasons, but has been restored each time. On April 24, 1964, the statue's head was decapitated off and stolen by politically oriented artists of the Situationist movement, amongst them Jørgen Nash. The head was never recovered and a new head was produced and placed on the statue. On July 22, 1984, the right arm was sawn off and returned two days later by two young men. On January 6, 1998, the statue was decapitated again; the culprits were never found, but the head was returned anonymously to a nearby television station and reattached on February 4.