DI Peter Cavanaugh is a character who appeared as an NCS and Australian authorities representitive in 2004 when DI Neil Manson was using his old DS; Don Beech as an informant whilst the latter was in prison. Cavanaugh first asked who wanted to know why Manson was talking to Beech. Manson revealed that info on an up and coming robbery involving an Australian criminal called Jason Black, who Don Beech worked with whilst he was on the run in Australia in 2001. The robbery goes pear shaped and Beech is assaulted in prison, and Cavanaugh gives new info on a second robbery, given by his current love intrest, DS Samantha Nixon, and the robbery goes ahead but PC Cameron Tait and Nixon are held at gunpoint whilst undercover on the boat, but DS Phil Hunter disables the getaway boat and intervenes. A robber tries to shoot Phil but SO19 take him down. Manson suspects that there is someone on the inside, and Beech gives them info on Cavanaugh. Nixon is 'suspended' and goes undercover to expose her new lover, and he takes her hostage while he tries to escape, but Beech gives them tapes of him discussing the robbery, and the airfield where he is taking off from. TSG escort Manson, Hunter and Beech to get the tapes, then to his new Category C prison, but Beech and girfreind Margaret Black overpower Phil and Neil and Beech escapes. To get a lesser sentence Cavanaugh tries to frame Manson for letting Beech escapes. Manson is cleared and Cavanaugh is jailed.