Andy Burnham is leaving the shadow cabinet to focus on his campaign to become the next mayor of Greater Manchester.
The shadow home secretary and former leadership contender told the Labour Party conference: "It is time for me to turn my full focus to Greater Manchester.
"That's why I can tell you all first today that I have asked Jeremy to plan a new shadow cabinet without me, although I will of course stay until it is in place.
"I have given my all to this Party and always put its interests above those of factions and personalities. And I have given exactly the same loyalty to all four of the Labour leaders I have served."
The mayoral election will take place in 2017 at the same time as scheduled local elections in May.