Sir Keir Starmer has declared it his "moral mission" to "turn the tide on the lost decade of young kids left as collateral damage".
The government launches its 10-year youth plan today, which has pledged £500m to reviving youth services.
Culture Secretary Lisa Nandy has also warned that young people are now "the most isolated in generations" and face challenges that are "urgent and demand a major change in direction".
But despite the strong language, the Conservatives have warned that "under Labour, the outlook for the next generation is increasingly bleak".
Lisa Nandy is on Sky News from 7am - follow live
Launching the 10-year strategy, Sir Keir said: "As a dad and as prime minister, I believe it is our generation's greatest responsibility to turn the tide on the lost decade of young kids left as collateral damage. It is our moral mission.
"Today, my government sets out a clear, ambitious and deliverable plan - investing in the next generation so that every child has the chance to see their talents take them as far as their ability can."
What's in the government's strategy?
Under the plans, the government will seek to give 500,000 more young people across England access to a trusted adult outside their homes - who are assigned through a formal programme - and online resources about staying safe.
The prime minister said the plans will also "ensure" that those who choose to do apprenticeships rather than go to university "will have the same respect and opportunity as everyone else".
The plan comes following a so-called "state of the nation" survey commissioned by Ms Nandy, which heard from more than 14,000 young people across England.
Launching the strategy, she said: "Young people have been crystal clear in speaking up in our consultation: they need support for their mental health, spaces to meet with people in their communities and real opportunities to thrive. We will give them what they want."
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But the Conservatives have criticised the government for scrapping the National Citizen Service (NCS), which ended in March this year.
Shadow culture secretary Nigel Huddlestone said "any renewed investment in youth services is of course welcome", but said Labour's "economic mismanagement and tax hikes are forcing businesses to close, shrinking opportunities while inflation continues to climb".
(c) Sky News 2025: Starmer warns of 'lost decade of kids' - as he launches 10-year youth plan
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