Troughton played the time-travelling doctor as an introspective crank trapped in a pair of outsized Rupert the Bear strides (aka the Time Trousers). Pertwee, sporting a leonine perm, was a caped crusader: dashing, clipped of accent and with a fatherly eye for his scantily clad, cutesy-bunny assistants whose job was to scream and show lots of leg whenever they spotted something nasty in the BBC's props department.
Tom Baker decided to be Soho's very own Tom Baker, long of scarf, fedora perched on a shock of curly hair, rolling eyes, and an infectious giggle that suggested the doc might be fond of the odd tipple between sojourns through the space-time continuum. Early episodes in the time-cheating series (it began in 1964 with William Hartnell as the doctor) were clearly cobbled together on a shoestring. The first Whos battled with Daleks and Cybermen in the confined corridors of wobbly space-age studio sets or in a quarry seen so often that one suspected Dr Who of keeping it in the infinite recesses of the Tardis.
McGann's Dr Who will have much more dosh behind him; the new story is set in San Francisco (the real, sunny, flowers-in-the-hair thing) as Doctor Who has proved very popular in the US. But before addicts accept the doleful McGann, two pressing questions need answers: where, how, and when will the MkVI doctor meet the Daleks? And, will McGann go the way of all ex(terminated) Dr Whos and disappear into some mysterious interstice in the Thespian space vortex, never to be seen again?
! 'Doctor Who' will be shown on 27 May, BBC1.