Theatre producer Paul Kelleher, 37, attacked the statue last July with a metal barrier, after his first blow with a concealed cricket bat failed to cause any damage, London's Southwark Crown Court was told on Wednesday.
Mr Kelleher told police he felt driven to behead the 8ft statue as soon as he heard it was going on show at London's Guildhall.
He felt the £150,000 statue represented the ills of the world's political system, the court heard.
Inevitable arrest
His second blow to the work of art's "big nose" severed the statue at the neck, the jury was told.
The court heard once his "act of vandalism" had been carried out, he waited quietly by statue of the former prime minister for his inevitable arrest.
When police arrived minutes later he said: "I think it looks better like that."
Guy Ladenburg, prosecuting, said: "Not surprisingly police didn't agree with this last assertion of his and arrested him for criminal damage."
Publicity stunt
Mr Ladenburg said press reports triggered a "keen interest" on Kelleher's part, "not as an avid fan of the former prime minister, nor as an admirer of sculpture.
"It represented for him an ill-conceived publicity stunt."
Kelleher of Loring Road, Isleworth, west London, who did not deny attacking the statue when interviewed, denies one count of criminal damage.
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