An environmental protester sloshed green custard into the face of British cabinet minister Peter Mandelson's face as he arrived at a low-carbon-economy summit Friday morning.

Leila Deen, an activist from the environmental group Plane Stupid, which opposes the expansion of Heathrow Airport west of London, covered the politician's face in pea-green goo as he got out of his ministerial car.

He immediately went inside the building as Deen watched.  She then calmly walked away.

Deen told Sky News she was protesting about reports that Lord Mandelson had met lobbyists from Heathrow owner and operator BAA Ltd. before the government gave the controversial go-ahead for a third runway at the London airport.

Talking about the goo, Deen said: "It's green custard. I could eat this right now -- it's totally harmless."

She went on: "The only thing green about Peter Mandelson is the slime coursing through his veins."

Click here to read the rest of this story from Sky News.