Mannion played an instrumental part in the removal of Brownlow following the Don Beech scandal, and the appointment of Brownlow's replacement, Tom Chandler.
Mannion himself was succeeded as Borough Commander by Jane Fitzwilliam, and his fate was never explained.
DAC Pearson tells him that the rumour is groundless.
He has a relationship with PC Andrea Dunbar, and was about to leave his wife Philippa for her when he realised she was an undercover journalist.
Despite this, he agrees to give them a chance but she is killed in the second Sun Hill fire.
Angry at the interference into his personal life, Manson organises to have Eva reassigned, blackmailing DCI Meadows over his relationship with a prostitute.
Manson gains many collars and much credit for using information provided to him by DS Don Beech, the detective who puppy-walked him in CID.
An ambitious DI, Manson seeks to discredit DCI Meadows where possible, and quickly becomes unpopular with his exacting requirements and seemingly sexist attitudes.