The most pampered animal in history was Incitatus, Caligula's horse, which slept in a stable of marble and was fed oats mixed with gold flakes, according to Suetonius. This week, however, Incitatus acquired a latter-day rival in the form of Trouble, a Maltese terrier dog.

Trouble's owner was Leona Helmsley, the property developer who died last month. Helmsley, once known as the "Queen of Mean", was devoted to the dog during her life and demonstrated it in death: she left Trouble a $12m (£6m) trust fund in her will while four of her grandchildren got $5m each.