LONDON, England (CNN) -- A 29-year-old woman has been arrested in connection with a custard-throwing attack on British Business Secretary Peter Mandelson, a Metropolitan Police spokesman told CNN Sunday.
Mandelson: "Thankfully, it wasn't paint and I've come through it intact."
A woman was seen on television images Friday throwing a green slime-like liquid in Mandelson's face as he stepped out of his car to attend a meeting on carbon emissions. The act was a protest against the expansion of London's Heathrow Airport.
The woman was not identified by police, but Plane Stupid, a group that opposes airport expansion and aviation-related climate change, identified her as protester Leila Deen.
"It's not right that someone like Peter Mandelson can stand up and talk about being green," Deen said. "The only thing green about Peter Mandelson is the slime coursing through his veins."
Police said the woman went to a police station in central London by arrangement on Saturday, and has been released on bail. She has not been charged, but is scheduled to return at a later date in April, the police spokesman said.
Deen said she disguised the custard in a disposable coffee cup with a lid. "It was a grave decision that I had to take to highlight this, but we cannot have people like Peter Mandelson standing by and being applauded for his actions on climate change when he's agreed to the third runway and bullied others into that," she added. Watch Mandelson get "slimed" »
After the incident, Mandelson said Deen failed to make her point.
"She was so busy throwing what seemed like green soup or something in my face that she failed to tell me what the protest was about," he said, adding that he wanted to get on with his meeting "and not bother too much with adolescent protests."
It was the second high-profile action in a week by Plane Stupid, which has become known for headline-grabbing stunts. Last Tuesday, nine of the group's protesters broke into the grounds of Aberdeen Airport in Scotland and delayed flights for several hours in a demonstration against expansion.
The British government voted in January to approve a controversial third runway at Heathrow, saying it will increase airport capacity and is essential for British business. The government has promised noise and emission levels will actually be reduced as Britain meets European Union targets.
Heathrow currently operates at 99 percent capacity. The runway's construction would involve razing areas around the airport, including an entire village and parts of two other towns. Opponents say emission levels will increase under the plans.