03/08/2026
Clive Hammond
He has extensive strategic partnership experience, working with the Home Office and speaking nationally on system thinking.
ACC Darren O’Callaghan joined Thames Valley from Hampshire & Isle of Wight Constabulary in April 2026 and has 31 years’ service within policing.
He began his career in 1994 as a PC in Petersfield, Hampshire. Then, in 1997, he became a detective working across crime, intelligence, and local policing, including the force’s Crime Unit.
Following this, he worked across Professional Standards, Child Protection, Major Crime and Intelligence, and as District Commander for Fareham and Gosport.
He then progressed through the ranks to become the Director of Intelligence in 2015 and the Head of Intelligence, Tasking and Development as a Chief Superintendent in 2017 before moving to the Joint Operations Unit in 2022.
His work across both forces continued in his role as T/Assistant Chief Constable, responsible for the Joint Operations Unit and Contact Management.
He has extensive strategic partnership experience, working with the Home Office and speaking nationally on system thinking. He continues this collaborative work with JESIP (Joint Emergency Services Interoperability Protocol) and is one of a number of specialist firearms commanders within Thames Valley.
ACC O’Callaghan said: “In the past few weeks, the force has been highlighted by HMICFRS as making significant improvements, but also highlights areas to work on. I am looking forward to the challenge of doing all I can to help Thames Valley Police become an excellent force trusted by all of our communities.
“It will be a privilege to be working with our brilliant officers and staff, building on the drive to improve our investigative capability, support victims of crime, preventing harm and ensuring we achieve the best possible outcomes for them, and protect the public across Berkshire, Buckinghamshire and Oxfordshire.”