not a Phone booth, a Police Box, there is a different, police boxes are free, and for emergencies, phone booths aren't free. And it is called the TARDIS which stands for Time And Relative Dimension In Space.
FYI the show was never cancelled. They just stopped making episodes of it. Hence the 3rd question on the bbc's FAQ. When will Doctor Who come back? Currently it is back as a radio show on bbc radio 2 but as for a tv series, who knows? Ran from 1963 until 1989. Not bad for a tv show that original started as part of the BBC's childrens lineup (it was broadcast just before Blue Peter, which coincidently is one the longest running kids show of all time.)