Humberside Police chief constable, Justine Curran, has announced her retirement from the top position.
Ms Curran, who has given almost four years to Humberside Police, said "it is time to pass on the baton and let someone else lead the force".
Her deputy, Garry Forsyth, will assume interim command of the force until a replacement has been recruited.
Ms Curran said: “It was not an easy decision to leave something that I am passionate about and have given huge commitment to. I am proud of the significant impact we have achieved working every day to make Humberside safer and stronger.
"Humberside remains a very safe place to live, work and visit”.
She added: “However I feel the time is right for the next chapter and having discussed this with the Police and Crime Commissioner, who is about to launch the new Police and Crime plan, I feel that it is time to pass on the baton and let someone else lead the force to deliver the aims of this plan.
"I would like to thank my colleagues past and present, officers and staff for their commitment and support”.
During her time as chief constable, Ms Curran faced criticism after Her Majesty's Inspectorate of Constabulary (HMIC) identified severe flaws in June 2015.
But she oversaw the force's improvement as it upgraded to 'requires improvement' from 'inadequate' last year.
In a statement, Humberside Police and Crime Commissioner Keith Hunter said: “Justine Curran has given almost four years’ service to Humberside Police and prior to that has served in a number of other forces, including a period as chief constable of Tayside Police in Scotland.
"It is a mark of her commitment to Humberside Police and the public it serves that she has agreed to make way for a new chief constable who can tackle the continuing challenges the force faces, including those identified by HMIC in their reports over the last few years. As Police and Crime Commissioner, I wish her well and thank her for her service to the force.
“I am committed to tackling the issues Humberside Police faces as I made clear when I was elected. I now want to move swiftly to appoint a new chief constable who can lead Humberside Police on the next stage of its development."