I was watching The Stolen Earth again (for the upteenth time), and you know how it is, when you notice things that you didn't initially. Well, when Harriet Jones made contact via a subwave communication link, I noticed the incoming message beep - duh-duh-duh-duh-duh-duh-duh-duh. It occurred to me that it was in parallel with that of the Master's table tapping and as a subliminal mind control mechanism to make people 'Vote Saxon' and through the Archangel Satalite Network -
An earthwide mobile phone satellite network (made up of 15 satellites overall) seen in 'The Sound of Drums'. The Archangel network creates a low-level, worldwide telepathic field which allows the Master to subtly influence the behaviour of the entire planet, first by convincing a substantial number of the British public to vote for his Mr Saxon persona and later to keep most of the human race afraid of him. It also masks his Time Lord nature from the Doctor. In 'The Last of the Time lords', the Doctor uses the network to channel the combined psychic energy of the entire human race, Martha having convinced them to think of the Doctor by name at the same moment.
It affected 98% of the British population by hypnotising them to Vote Saxon.