Is it true that Tom Baker (Dr Who no.5(?)) was once the voice of the Speaking Clock
No -- Not the British GPO/BT clock anyway. The people above are the only ones who have ever provided the voice.
Tom Baker did do a lot of narrations for TV shows, voiceovers for commercials, etc. Maybe you're thinking of something like that?
Oh, and he was the fourth
1. William Hartnell, 1963 - 1966
2. Patrick Troughton, 1966 - 1969
3. Jon Pertwee, 1970 - 1974
4. Tom Baker, 1974 - 1981
I suppose you could count him as the fifth though if you include the fact that Peter Cushing played the Doctor in the two 1960s films!
I just realised that my keyboard has no hash key
Not on shift-3? That's weird. U.K. PC keyboards have it over on the right near the return key because £ is above 3. Horrible layout!