There are a couple of references to The Professionals. Malone begins his induction speech to new CI5 recruits by quoting George Cowley, the man who founded the organisation and who was in charge of it during the original show. The quote of Cowley's that Malone uses is heard during an induction Cowley himself gives to new CI5 recruits in the episode Old Dog With New Tricks. Sam tells Chris that they used to have an agent with a perm - a probable reference to Martin Shaw's character Ray Doyle. The episode ends with Malone saluting a photograph of George Cowley.