The Conservatives "are running our country down in every way", Jeremy Corbyn will say, as Labour's battle lines are drawn ahead of next month's local elections.
Mr Corbyn is expected to highlight falling life expectancy for British pensioners and those aged 45 as he launches Labour's local election campaign.
His speech in Newark, Nottinghamshire, on Tuesday comes amidst fresh poor polling for the party and claims Labour could lose further ground to the Conservatives when voters head to the ballot box on May 4.
Mr Corbyn is expected to say: "How can you not be angry and demand major change when life expectancy in Britain for pensioners and those aged 45 is falling?
"We are a rich country, the sixth richest in the world. We are not at war, there is no epidemic sweeping our land.
"So how on earth can life expectancy be falling? The truth is that the Tories are running our country down.
"Home ownership, opportunities for our children, wages and conditions at work, the NHS, care for our elderly, and now life expectancy: they're all going backwards, run down by a Conservative Government that looks after those at the top and manages decline for the rest of us."
Local government elections will be held across England, Scotland and Wales, alongside a number of mayoral elections in city regions such as Greater Manchester and the West Midlands.
Election expert Professor John Curtice has said there could be a 12-point swing from Labour to the Conservatives in May's contests, with Mr Corbyn's party at risk of losing control of councils in Nottinghamshire and Derbyshire.
The latest Guardian/ICM poll, meanwhile, put Labour at 25%, their lowest support in these polls since the 2015 general election and joint equal to their lowest performance going back to 1983.
But Mr Corbyn will argue that "Labour is standing up for you", pointing to initiatives run by Labour councils across the country.
The Labour leader will add that the UK must "look to the future" as we "ask ourselves what sort of country we want Britain to be."
"Theresa May's Government is trying to use Brexit to turn Britain into a low-wage tax haven for big business," he will say.
"We are offering a real alternative that reflects the priorities of the majority of our people to rebuild and transform Britain, so that no one and no community is left behind.
"Instead of a country run for the rich, we can create a Britain where all of us can lead richer lives: investing in a better Britain, creating educational opportunity for all, guaranteeing the health and social care services you need, providing safer neighbourhoods and building homes people can afford.
"This election is your chance to send a message to the Tories, that you won't accept our NHS in crisis, your children's future betrayed, a deepening housing crisis, damaging cuts to the police and insecure jobs that don't make ends meet."
Nominations for local elections across England and Wales close on Tuesday at 4pm.