This just flashed my way from Douglas McPherson:
"As the evil clown craze sweeps the UK, Zippos has turned it into a
publicity opportunity by removing clowns from the show. Not strictly
true, as revealed on my blog, but still a reflection of how the pranksters have unsettled the pros."
Or scroll down to the Circus Mania link on the right sidebar
As reported also in The Sun: "Martin ‘Zippo’ Burton, who used to be a clown himself, is worried the ‘killer clown’ trend will affect his shows."