Frontier in Space Day couldn't make it to the end of the story (the day when only an episode of Frontier has made its debut but no other story or spin-off). Part Six went out today in 1973, but a significant episode of the new series also made its debut today.
It wasn't Freema Agyeman's introduction on this date in 2007, but it was that of Martha Jones. Smith and Jones got Series 3 underway with a platoon of Judoon upon the Moon.
As well as playing Adiola in Army of Ghosts in Series 2, Freeman had also been introduced as the new companion at the Doctor Who Concert in Cardiff just before Christmas.