One aspect that was irritating me from the beginning, was, that Vaughan was able to reach Lucas / John on his business mobile phone. This number would be secret and only known by other members of the secret service with special data access or Lucas own department.
Who was the leak or why did Vaughan have better data access than Lucas himself?
Lucas / John can’t reach Vaughan’s data, but Vaughan can reach his, though he is not officially working for or inside MI-5.
How strange! Why was Vaughan so important for the MI-5 that they secured his files with such a high access level (A)?
His further way did not show a hint of his importance. Harry Pearce did not really set his trust in his value as informer. The information Vaughan gave at the meeting with Harry Pearce in episode 9.7 was not really valuable, as this must have been the information Harry already knew before the meeting.
Is the security level for Vaughan’s files just an element to make him a more fearful opponent for Lucas / John?
Is his ability to reach Lucas / John at any moment he chooses serving the same purpose?