The middle class charity worker who covered Lord Mandelson in green custard on live television today is a veteran of direct action campaigns since childhood.

Leila Deen’s commitment to the environment meant that for her mother’s recent 60th birthday the family spent three days travelling to Morocco by train as she would not allow them to fly.

Ms Deen, 29, says she is part of a new generation of protest movement. She recalls being inspired by a film about the fight against apartheid in South Africa and said she has read about Gandhi and the Suffragettes, but she argues that direct action needed to be upgraded for the modern era.

“We are inspired by history but we are a new generation,” she said. “We try and do it in a light-hearted way and our methods are maybe a bit more dynamic.”

The daughter of a primary school teacher, she grew up in Brighton and started campaigning as a child when her elder sister took her to the protests against a bypass at Newbury, Berkshire. At 16 she was marching against the introduction of student grants.

Her first brush with public controversy came when she voted for her university shop to stop selling The Sun newspaper. After completing her degree in international studies and politics at Leeds, she went on to do a masters at Sussex University in a similar field before working.

Ms Deen now lives in Hackney, East London, and works for the World Development Movement, focusing on alleged attempts by Western governments to force developing countries to privatise their water supplies.

She has been involved in the Make Poverty History campaign and attended the G8 summit at Gleneagles in 2005, during which she occupied a crane, and in Germany in 2007.

Throwing green slime over Lord Mandelson was the latest of a string of outbursts since joining Plane Stupid, the anti-aviation campaign. At the time of the group’s rooftop protest at Parliament last year, Ms Deen presented herself as the public face of the anti-aviation movement

She recently appeared with protesters in Victorian robes at Heathrow and was one of three Plane Stupid protesters who sounded horns during a speech at an environmental conference by Geoff Hoonm the Transport Secretary, earlier this week.

Ms Deen explains the links between her apparently disparate interests: “What I realised is if you care about people in the developing world you have to care about climate change because they are the people who will feel it first and feel it worst."

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