This doesn't come as any surprise, but apparently a significant minority of drivers still use handheld phones for quick calls whilst driving. Even worse, almost 10% admit to doing so on a regular basis. These figures are from What Car? and paint a far worse picture that official figures.
What Car's editor suggested that all new phones be sold with a hands-free kit by law, in spite of the fact that such a setup has very little effect, compared to handheld use, on reducing driver distraction. The only reason that hands-free use hasn't been outlawed (other than the fact that it wouldn't be 'popular' with this image-obsessed government) is that it would be impossible to police as there aren't the resources (or the technology?) to accurately detect mobile phone signal transmission points.