You never really know how quick you are before you reach F1.

You tend to think that there is a big gap between F1 and everything else. F1 is where all the fantastic drivers are, so you just don't know how good you are until you get there.

I have never won a race, and that is my main disappointment - but you have to be positive.

When I do retire, I know for a fact that I'll never be able to replace the incredible feeling I get when I'm driving an F1 car.

Williams is one of the big names in F1 with a really strong pedigree, so it is an honour to be driving for them.

When you drive a car, either you manage it and feel it with the grip of the car, or, like me, you fix it on visual speed. If you do it through the grip, you lose it very quickly - because when the track changes, you can have scares. I do it visually, so if I am going too fast I fight to get the car back, but I do not do it by feeling the grip.