Merseyside police and crime commissioner Jane Kennedy has paid tribute to retiring Assistant Chief Constable Andy Ward.
Mr Ward will be replaced by returning ACC Nikki Holland.
He joined the Force in 1983 at the age of 20.
Jane said: “Andy has been a dedicated servant to the police service and to the people of Merseyside.
“We will miss his operational experience, knowledge and expertise and also his charm and sense of humour.
“He is going on to other important work for the police service nationally and I wish him well.
“Andy has given almost 33 years of dedicated service to the communities in our region, leading the fight against serious and organised crime as the head of Matrix, tackling the threat posed by terrorism and taking charge of some of the Force’s most important operations.
“Today is an opportunity for me to thank Andy for his dedication and commitment over the last three decades.
“I would like to wish him a happy and healthy retirement and all the very best for the future.
“It is also an opportunity for me to warmly welcome ACC Nikki Holland back to Merseyside and wish her every success as she takes up responsibility for the Matrix Serious and Organised Crime Portfolio.
“Nikki is the fourth generation of her family to serve as a police officer in Liverpool and she has a wealth of experience that I am sure she will put to excellent use as she takes up this important role.
“I was delighted to meet Nikki again earlier this week and I look forward to working with her as she helps to deliver our policing priorities, to make Merseyside an even safer place to live.”