When neuroscientist Baroness Susan Greenfield arrives for her interview she's dressed in a smart little number – a light grey Emporio Armani mini-skirted suit teamed with knee high platform black leather boots. Not so surprising when you consider she's best known in the press as a flamboyant dresser, debunking the notion that scientists are stuffy individuals, smoking pipes and wearing slippers in front of a log fire. What may be slightly more eccentric though is the fact that before lunch she was wearing something completely different. A mid-day shopping trip later and she's changed into the day's purchase. And as she says, "I have to confess, I think you've either got the clothes gene or you haven't. I just love clothes."

But don't be fooled by the outward appearance. This is one sharp cookie. Greenfield's appearance may be more swish advertising agency than science but when it comes to her professional work this woman is hot.

Greenfield has perhaps done more than most scientists to bring her world into the public arena. So it's very apt that she's been director of the Royal Institution since 1998, an organisation that prides itself on making science accessible. Prior to that, in 1994, she was the first woman to be invited to give the Institution's Christmas lecture. And this April the Royal Institution is re-opening after a two and half year restoration. She says, "I'm very pleased this is all happening on my watch. The Queen will be opening it. That will be another big moment, and another outfit will be needed."

The sartorial side of Greenfield is always present. But don't be deluded that she's blissfully unaware of its impact. She recognises that she 'attracts a lot of criticism'. But she says, "I can't take that seriously or to heart unless I know specifically what the issues are. I do think anyone who is different in any way will attract criticism. I think if I was a conventional member of science I would resent slightly someone who walked around in mini-skirts and seemed to be in the press a lot and who's science I don't really understand - someone who is left of field. And more over if that person glibly dismissed the kind of work I did, that was my life's work, I'd feel slightly fobbed off, slightly resentful." However, although she may think she's perceived as doing those things, she strongly argues that's not the case. But the point is, regardless of how she appears, at heart she's an extremely committed scientist.

For Greenfield being a 'free agent' is very important. She likes to 'plough her own furrow'

That Greenfield may seem out of step with her contemporaries she puts down to her early years. She explains, "I think it's partly because my dad's Jewish, my mum's Christian. In the 1950's there wasn't so much anti-Semitism but the Jewish community was an ethnic minority. Anyone different from being Protestant kind of stood out. So Jewish was a bit weird. Being half Jewish, half Christian; a working class girl in a middle class school; an only child and then having a brother 13 years younger, and interested in the sciences and then the classics, meant that I've always chosen the lesser path."

For Greenfield being a 'free agent' is very important. She likes to 'plough her own furrow'. As she says, "I've always been an eccentric. Heavens, why be the same as everyone else?" Her path to science came through the classics at Oxford University to philosophy, psychology and finally neuroscience.

She spends half the week in London at the Royal Institution and the rest of the time in Oxford where she stills keeps a lab with a minimum of ten people working there. She has two major scientific ambitions; to discover how the brain generates consciousness and to find a medication 'that works for Alzheimer's'. She explains; "Neurodegeneration is like cancer was in the '50's. You'd whisper the C word. We know it's a serious disease but it's not necessarily a death sentence.

With Alzheimer's there's nothing you can do apart from making it as comfortable as possible and slow it down. My thinking is that in 10 to 20 years time neurodegenerative disease may be more like cancer is now. We'll know a lot more about diagnosis; more about what's causing it and perhaps medication to slow down the death of the brain cells, to stabilises it, or perhaps keep people as they are." Combine that research with what Greenfield sees as the 'ultimate riddle' – consciousness – and you begin to understand her when she says "I feel I'm on short time." She wants to 'eek out every single minute. I just cram it all in and luckily I've inherited some good genes. My dad's 92 and my mum's 80. But I do abuse my body. I love drinking, especially champagne. And I eat really badly, I eat on the hoof."

She's 'very anxious to work with Arab states' and is 'very proud to have met one-to-one with President Mubarak', of Egypt, something she say you wouldn't expect from a half Jewish woman.

For Greenfield there is no work/life balance, 'it doesn't get compartmentalised and implies that work is unpleasant'. She's on record as saying that she hates the phrase 'chilling out'. "To chill out implies that you're doing something excessive from which you have to rest. I know I'm in a monumentally privileged position where I enjoy my work. What scares me is not obesity, it's not junk food, it's the fact that human beings with these fabulous brains have ended up in scenarios that destroy their souls."

It's clear talking to Greenfield she takes nothing for granted and is fully engaged in the moment. She doesn't crave accolades but is very flattered when they come her way. She has several honorary degrees, received the CBE for her contribution to the public understanding of science, was given the French Legion d'honneur and created a life peer. She acknowledges she doesn't fit in but says, "It's more important for me to do the things I enjoy, and if the price I pay means that I'm unpopular or people say nasty things behind my back then that's OK." Greenfield says, "I'm very grateful that fate has dealt me this hand. That I am who I am rather than defined by caste or creed."

There are some glittering prizes that would define her contribution to science in the eyes of her peers, such as the Nobel Prize; something her mother obviously believes she deserves, as demonstrated by a story Greenfield relates surrounding her peerage. "They say you mustn't tell anyone, keep it utterly confidential. I was dying to tell my mum. I was going to Australia and I said to her, something really nice has happened to me and there's a small chance before I get to tell you that you may read about it in the newspapers. If that's the case I'm really sorry, but it's too important and I can't tell you because you mustn't tell a soul and I know you will. My mum said I can guess what it is, you're pregnant. I said we wouldn't have to wait to read about that in the papers. And then she said, I know you've won the Nobel Prize."

The future for Greenfield no doubt holds many more shopping trips for clothes. She'd like her friends to throw parties where she could dance the night away – her mother was a dancer – instead of sedately eating dinner. Most importantly she will continue her life's work to unravel the mystery of Alzheimer's. At the Royal Institution the plan is to go international. They already have a media centre in Australia where they're setting up a sister organization. She's a trustee of the Alexandria library and she's 'very anxious to work with Arab states' and is 'very proud to have met one-to-one with President Mubarak', of Egypt, something she say you wouldn't expect form a half Jewish woman. Add to that her new book being published in May about our individuality being under attack from new technology and the rise in fundamentalism, and her ambition to write a novel; it's very clear that Greenfield won't leave this world without making even more of a mark than she already has. She says, "Increasingly in life I go with things intuitively that are right for me." And up until now that appears to have worked very well.

The Royal Institution, 21 Albemarle Street, London, W1S 4BS. (+44) 0 20 7409 2992

'ID: A Quest for Identity in the 21st Century' by Susan Greenfield will be published on 15 May by Sceptre, £16.99

By Michele Nevard