Queen's Witness - A Mystery Where Three Worlds Collide in Violence by Peter Watson

Queen’s Witness is a tense political thriller set on the edges of London’s criminal underworld that overlaps with Fleet Street and Westminster. After it appears that the government’s Witness Protection Programme has been broken, investigative journalist, Matthew Kent, is lured into making a dangerous error of judgment, when the ensuing spiral of violence and mystery threatens not only his life but also those of both his lovers.