Alex Klein

Alex Klein was the senior aide to Harriet Jones in Downing Stret in 2006. He was with her when she was teleported aboard the Sycorax ship. Her premiership crumbled when the Doctor whispered to Alex, "Don't you think she looks tired" - six words that began a chain reaction leading to her downfall. It is probable that he leaked the information to the media.

Since Jones narrowly survived the vote; she presumably sacked Alex. Jones lost power at the 2008 general election(DW: The Christmas Invasion)