Boris Johnson was left dangling in mid-air when he got stuck riding a zip wire as part of a London 2012 Olympic event.
The Mayor of London was in Victoria Park where the Games are being shown live on big screens.
Mr Johnson decided to try out a 45-metre high, 320-metre long zip wire, as part of the festivities.
But he was left hanging for several minutes as the wire lost momentum and got stuck over a crowd of people.
As onlookers snapped photos on their mobile phones, Mr Johnson joked: "This is great fun but it needs to go faster."
Boris' spokesman was quoted in the Evening Standard as saying: "The judges will rightly be marking him down for artistic impression."