I have to be up by 7 and it takes me 10 minutes to get ready for school. It’s a boys’ grammar, but there are 25 girls in my sixth-form year. Our uniform is a skirt or trouser suit in black or dark grey, white shirt and black V-neck jumper. Breakfast is a strawberry or some other fruit on my way out of the house — I’ve lost three stone over a couple of years. I’m vegetarian, so I take iron, but I’m rarely hungry.

Before I passed my driving test, it took 90 minutes to get to school by public transport. Now I have first call on the family Toyota Yaris. I leave at 7.30. I drop my dad off at the station — he gives science advice to parliament and the government — and, in the week, it’s the only time I see him. My radio pre-sets are Classic FM, Virgin and Radio 2. I’m so tired, I just want music. No offence to the Today programme, but there’s no way I’m listening: it doesn’t give me a very enthusiastic view of the world.

On Wednesdays and every other Friday I’m allowed to leave school at 1.15 to work at home. Other days I’m too busy to eat lunch, but I always drink water. I’ve still not really settled in at St Olave’s. I was head of house at my old school, Wallington High School for Girls, and I miss my friends and that feeling of safety. But I moved so I could take Latin. And it’s good to push yourself out of your comfort zone. Now I’ve applied to Warwick and Oxford to read politics and history.

Music is a huge part of my life. It’s always got me through bad times. I’d love to see a music-teaching system like the one in Venezuela, which is available to everyone from the age of three. Schubert is my current favourite. I’m so jealous of my brother, Daniel, a brilliant cellist. We argue but we are very close, especially since he was so ill — he ruptured his kidneys on a skiing trip not so long ago.

I play violin and piano. I have a piano lesson once a week and try to do two hours’ violin practice a day. On Saturdays I’m at the Royal College of Music from 9am. On Sundays I play with the Stoneleigh Youth Orchestra in Wimbledon. And two nights a week I’m at the Royal Ballet School working on a composition and choreography project.

My other passion is politics. One of my earliest memories is from the age of two: wearing a Labour-party rosette and campaigning with my family. So many people my age aren’t interested in politics, but they don’t realise what’s been done for them since 1997. Now we have a fantastic minimum youth wage, the EMA [educational maintenance award], and Working Tax Credits. Just because I’m 18 doesn’t mean I can’t try to make things better. Call me sad, but I’m interested in education, health and pensions — they’re as important as global warming and supporting protests in Burma. I work for the Labour party at least one night a week. My political hero is Tony Blair.

My parents were in France when I had to go before the selection committee. Nobody even knew I had my name down. I had to drive to Shoreham on my own — the first time I’d driven on the motorway. I had to go through the selection process against two others. When I was 18, my grandfather phoned to wish me happy birthday, and the next day announced he was putting his name forward as the Labour candidate for Kensington. He’ll have to do what I did and stand up in front of the selection committee; it’s an even less safe seat than mine, which has an 8,000 Tory majority.

Gordon Brown said he liked my speech at the Labour-party conference. Had he called a general election, I’d have left school and gone on the campaign trail full time. Politics — helping people — is way more important than my education. Now I’m looking forward to running a long, sustained campaign so I can best represent the concerns of the people of East Worthing and Shoreham.

I get in from school exhausted, phone Dad to touch base and chat about the day. I chill out with a piece of fruit, the papers and BBC News 24, the only thing worth watching at that time. I check internet news stories, my Facebook and e-mails. I had my first piece of hate mail last week, a rant from a woman who had something against the name Benn. But I don’t let someone swearing about me on the internet upset me. It’s hard enough dealing with normal 18-year-old things, like friendships, boys and A-levels.

Until July Mum was assistant political secretary to Tony Blair, and was never home till 7 or 8, so Daniel and I are used to being on our own. He eats cereal; I might make some pasta. As a family we get on so well because we’re probably only together an hour or so on Sundays.

I shop in Zara, Gap, Hobbs and Ted Baker. I’m always out Friday and Saturday night, staying at friends’ houses, clubbing in Covent Garden and, yes, sometimes getting drunk. It takes me an hour to put on make-up and decide what to wear. I probably change clothes about 10 times.

On weekdays I do my A-level work till very late. I like to have Ugly Betty, Grey’s Anatomy or The West Wing on in the background. My left hand is always covered in ink messages — assignments to finish and lists. I call my friends before bed. And I always check my Facebook one more time. On a good day I’m in bed by 11.30 but often it’s nearer 1.30am. So much stuff is going through my head, it’s hard to get to sleep.

Interview by Sue Fox. Portrait by Sam Green

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