Shoe-waving as a form of protest first grabbed the attention of a wider public in 2008, when Iraqi reporter Muntazer al-Zaidi famously lobbed a pair of black lace-ups at President George Bush during a news conference in Baghdad. But the gesture, widespread among anti-government demonstrators last week in Cairo's Tahrir Square, is an ancient one in the Middle East.
An Egyptian journalist and commentator, Mohamed Abdu Hassanein, describes "the raising of a shoe, or threatening to hit with a shoe" as "the worst kind of insult".
Quite why is lost in the mists of time. The symbolism is plain: shoes are dirty, and we dominate what's beneath our feet. Sandal-shaking was a sign of displeasure in Biblical times. The Gospel of Mark relates that Jesus told his 12 disciples: "If any town will not welcome you, shake the dust off your feet when you leave, as a testimony against them."
Saddam Hussein understood the semiotics of shoes, having had a mosaic of George Bush Sr, accompanied by the word "Criminal", installed on the floor of the Al-Rashid hotel lobby in Baghdad at the end of the Gulf war in 1991. He did this expressly so it would be trodden on by everyone entering the building. (The Iraqi dictator suffered from shoes, too. When one of the many statues of him in Baghdad was pulled down, the first response of locals was to beat it hysterically with their shoes).
In the west, shoe-throwing has generally been viewed more positively. Brewer's Dictionary of Phrase and Fable notes it was "long a custom in England to throw an old shoe . . . at the bride and groom when they go to the church to get married." (Today, we tie one to the couple's car.) And the 19th-century American poet Will Carleton wrote: "Old shoes enough, if properly thrown/Do bring good luck to all creatures known."
But there are signs that shoe-throwing is making headway as a protest gesture in the UK: a march in London in 2009 against Israel's action in Gaza ended with hundreds of shoes being hurled into Downing Street and protesters chanting: "Shame on you, have my shoe."