Natalie Bennett is preparing for the most important moment of her career when we meet outside the St Pancras Renaissance Hotel.

The Green Party leader will go head-to-head with the nation’s most senior politicians tonight (Thursday) in the only live televised general election debate involving all seven leaders from Britain’s major parties.

Five weeks ago, Ms Bennett was lampooned in the national press for the mother-of-all car crash interviews with LBC radio presenter Nick Ferrari.

The 49-year-old stuttered, stumbled and coughed as she was asked how her party would fund a pledge to build 500,000 new social homes, without actually providing a coherent answer to Mr Ferrari’s question.

It was an embarrassing episode which Ms Bennett put down to “brain fade” at the time and has resolved not to repeat this evening.

“It was a very bad moment,” she said. “It will keep following me, I’m utterly resigned to that.

“I particularly regretted letting down the Green Party on what is a great policy. I might not be as smooth as some people but my passion and belief in Green policies does shine through.

“I’ve been doing practices for the debate, with run-throughs a couple of times a week for the last couple of weeks. We have lots of people in the office competing to be their favourite hate figure!”

Next month, Ms Bennett will stand for the second time as her party’s parliamentary candidate for Holborn and St Pancras.

She has lived in the constituency, in Somers Town, for years having moved to the UK from her native Australia in 1999.

At the age of 23, Ms Bennett, an only child who grew up in Sydney, was involved in a car crash which killed her mother instantly. As fire took hold of the vehicle, Ms Bennett dragged her injured father to safety.

“It’s something that has shaped me,” she said. “It’s one thing I learnt to live with but never got over.”

Now a British citizen, Ms Bennett is less than complimentary about her homeland.

“There’s a strong strand of anti-intellectualism in Australian life,” she said. “There can be a narrowness in lots of aspects of Australian life. Australian politics has become extraordinarily right-wing.”

A journalist by trade, Ms Bennett enjoyed a prosperous career in the British press, working for The Times, The Independent and finishing up on the Guardian.

On New Year’s Day 2006, she woke to a political calling and decided to join the Green Party.

“It was a New Year’s resolution,” said Ms Bennett. “I was possibly slightly hungover, looked at the state of the world and thought, ‘I should do something.’

“I knew at some point I’d get out of journalism because you do many of the same depressing stories. At some point I felt I’d want to change the news rather than report it.”

In Somers Town, Ms Bennett lives with her partner Jim Jepps, a Green activist who works in a local bookstore. The couple met five years ago online, when they were both active political bloggers.

“He blogged something about me which was wrong so I corrected him,” said Ms Bennett. “He’d mixed me up with somebody else.”

Take a glance at Green Party policies and it is clear the party desire a top-down shake-up of the status quo.

Ms Bennett’s party wants a move to “local banks” for local people instead of multinational institutions, they are opposed to the hereditary principle of the Royal Family and wish to decriminalise the sale of marijuana and the possession of class A and B drugs.

In Holborn and St Pancras, Ms Bennett will have to topple a Labour majority of almost 10,000 votes to fill retired veteran Frank Dobson’s shoes.

She said: “A lot of people say, ‘I’ve been voting Frank for years’, not ‘I’ve been voting Labour’. For so many people society isn’t meeting their basic needs. People are looking at Labour and Tory and saying, ‘There are no answers there.’”