Twenty-three years ago Natalie Bennett was in a car crash in Australia which killed her mother Joy.

For the national leader of the Green Party it was a devastating moment which will stay with her for the rest of her life.

Now the Camden politician is supporting calls for 20mph limits across the borough, arguing that such a measure could prevent deaths on the roads.

“The basic fact is, if you get hit by a car at 20mph, you are more likely to live,” said Ms Bennett, who lives in Somers Town. “If you get hit at 30mph, you are more likely to die.

“Our argument is that where people live, work and shop there are positives to bringing in 20mph limits.

“We need our streets to work for the people. We need to be a more active society on two feet or on bicycles.”

In the past three years there have been more than 40 collisions between pedestrians and cars in Primrose Hill, prompting Camden Council to consult on introducing a 20mph zone.

In February there were new calls for such a zone to be created after a fatal crash in Haverstock Hill.

Ms Bennett said the loss of her mother in a car crash had “impacted on her life deeply”.

“It never goes away,” she said. “When it is close to you, it is constantly in the pit of your stomach.

“Two thousand, eight hundred people are killed year after year on our roads. People don’t talk about this. We need to make walkers and cyclists safe.

“If you walk between King’s Cross and Euston, the whole stretch of road has been arranged for the benefit of cars.

“There are no pedestrian lights and people have to linger on the curbs and guess when it is safe to cross.

“We have to make this a more pleasurable environment for everyone to live in. Islington have done it, so why can’t Camden? There is nothing revolutionary about this.”

Ms Bennett, 46, became the leader of the Green Party of England and Wales earlier this year.

Before becoming involved in politics the journalist, who joined the party in 2006, was the editor of The Guardian Weekly and has written for a number of publications including The Times and The Independent.

“It’s very good fun,” she said. “I have got to meet people from all over.

“One thing, though, that people keep saying to me is that they are frustrated by faux consultations. This is a problem across the whole of the country. A consultation is really asking people’s opinion. But people think they are a fix.

“On a bigger scale of things, we have to start thinking about changing the economy, bring manufacturing back to Britain, localising things.

“London was once surrounded by farms and the food supply was much more secure.

“There need to be more steady jobs which pay decently. I want to make sure the minimum wage is a living wage.

“It’s wrong that anyone working two or three jobs can’t afford to get on the Tube.”