Assistant Chief Constable (ACC) Darren O' Callaghan has started in the position today (3/8).
ACC O' Callaghan joined Thames Valley Police 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 becoming a detective in 1997 working across crime, intelligence and local policing, including The Force Crime Unit. He also has experience working in Professional Standards Child Protection, Major Crime and Intelligence as well as becoming the Director of Intelligence in 2015 and the Head of Intelligence, Tasking and Development as a Chief Superintendent in 2017.

Image of Darren O' Callaghan from Thames Valley Police website
Commenting on his new role, he said:
"I am delighted to be taking up my new role leading Crime and Criminal Justice for Thames Valley Police, and to have the opportunity to build on the great work here in the force.
"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."
Thames Valley Police say Darren has demonstrated a strong commitment to looking after people throughout his career; advocating the work of our Family Liaison Officer’s, working in Partnership to reduce the harm from Organised Crime as well as supporting the workforce.
He is also described as having 'extensive strategic partnership experience at the highest levels', working with the Home Office and speaking nationally on system thinking. He is also one of a number of specialist firearms commanders within Thames Valley.

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