The Mayor of London Boris Johnson was left dangling on a zip wire for several minutes when it stopped working at an Olympic live screen event.
He was trying out a 45m (150ft) high zip wire at Victoria Park, where the Games are being shown on big screens.
The wire then lost momentum, leaving him suspended "like an odd Christmas decoration" above a crowd of people.
As onlookers snapped photos, he joked: "This is great fun but it needs to go faster."
Lee Medcalf, who was at the event, said: "When Boris came down the zip wire, it was very James Bond-esque with him shouting 'Team GB'.
"However, he seemed to lose momentum and was left hanging there like an odd Christmas decoration for about five to 10 minutes. He spoke to the crowd, which had gathered beneath him, saying 'this is what it's all about; this is great, this is fantastic, this is Team GB'."
A spokesman for the mayor said: "The mayor has survived his first zip wire experience relatively unscathed.