When introduced in September 2007, Sybil, who was black and white, was the first cat at Downing Street since Humphrey was reportedly removed in November 1997, due to Cherie Blair's aversion to cats.
Saat diperkenalkan pada September 2007, Sybil, yang berwarna hitam-putih, menjadi kucing pertama di Downing Street sejak Humphrey dikabarkan dilepastugaskan pada November 1997, karena ketidaksukaan Cherie Blair terhadap kucing.