Starmer's party has a double-digit lead in the polls over the governing Conservatives, and both parties are making their pitch to voters, many of whom remain undecided, ahead of an election expected next year.
A tumultuous year in British politics left Rishi Sunak as prime minister after his two predecessors were forced to quit, and he has to deal with a cost-of-living crisis, high inflation, mounting hospital pressures and widespread industrial action.
Speaking a day after Sunak outlined his priorities for the year, Starmer will say that the multiple crises impacting Britain are a result of short-term "sticking plaster politics".
"Britain needs a completely new way of governing," Starmer will say in a speech in London, according to extracts released by Labour.
"You can't overstate how much a short-term mind-set dominates Westminster. And from there, how it infects all the institutions which try and fail to run Britain from the centre."
Starmer will say that a Labour government will decentralise power and be focussed on "national missions" to be announced in the coming weeks.
He has announced some of his plans to empower regions and communities while replacing the unelected upper parliamentary chamber, the House of Lords, but has given little policy detail in other areas.
On Thursday, however, he will spell out that the plans of a future Labour government would not be based around big spending.
"Let me be clear - none of this should be taken as code for Labour getting its big government chequebook out again," Starmer will say.
"Of course investment is required - I can see the damage the Tories have done to our public services as plainly as anyone. But we won't be able to spend our way out of their mess."
(Reporting by Alistair Smout; Editing by Angus MacSwan)
By Alistair Smout
