Adelphi

This Time Lord messenger was sent to Earth to warn the Third Doctor about the arrival of the Master.

Profile
He was dressed as an English businessman, complete with bowler hat and umbrella. His disguise was somewhat compromised by his first being seen to hover in mid-air, due to his co-ordinates having "slipped". He warned the Doctor that his (the Doctor's) old enemy, the Master, had arrived on Earth and might try to kill him. (TV: Terror of the Autons)