She may have voted against London mayor Boris Johnson last year, but film-maker Franny Armstrong was glad to see the cycling politician chase away would-be attackers in Camden, north London on Monday night.
According to a report on the BBC website, the climate change activist was walking home when she was approached by a group of hoodie-wearing girls, one of whom was brandishing an iron bar.
The mayor, who was cycling past, stopped and chased the girls down the street, calling them 'oiks'. A few minutes later he returned and escorted Armstrong home.
"I was texting on my phone so didn't notice the girls until they pushed me against the car, quite hard," Armstrong told the BBC. "I noticed that one had an iron bar in her hand – it was very frightening."
Armstrong called out for help from a passing cyclist, who turned out to be Johnson. She said: "He said to the girls, 'What do you think you are doing?' He picked up the iron bar, called after the girls and cycled after them."
Although Armstrong admitted voting for Johnson's Labour Party rival Ken Livingstone in the 2008 mayoral election, she said: "If you find yourself down a dark alleyway and in trouble I think Boris would be of more use than Ken. He was my knight on a shining bicycle."
Earlier this year Armstrong launched the 10:10 campaign, which calls for a 10 percent cut in carbon emissions in 2010. She directed the documentaries McLibel, Drowned Out and Age of Stupid.