The Conservatives have made our economy weak - much weaker than people realise.
An extra £100 billion will be pumped into combating climate change and protecting the environment if the Liberal Democrats take power, the party's finance spokesman will say.
Former Cabinet minister Sir Ed Davey will also launch an attack on the "fantasy" economics of Prime Minister Boris Johnson's Tories and Labour.
Sir Ed will use a speech in Leeds on Friday to say: "A Liberal Democrat government will jump-start an economy-wide programme to tackle the climate emergency.
"Across a five year Parliament, Liberal Democrats would spend and invest an extra £100 billion of public finance on climate action and environmental preservation.
"This includes a new £10 billion renewable power fund to leverage in over £100 billion of extra private climate investment.
"This will fast-track deployment of clean energy, to make Britain not just the world leader in offshore wind, but also the global number one in tidal power too.
"And we will invest £15 billion more to make every building in the country greener, with an emergency ten-year programme to save energy, end fuel poverty and cut heating bills."
Sir Ed will also attack the spending plans of the Government and Labour.
He will say: "The Conservatives have made our economy weak - much weaker than people realise. Too many people can't live a secure, happy and fulfilling life. And too many businesses face crippling uncertainty over their future.
"Yet so far, the economy debate in this election has been a debate between fantasies. Fantasies born of nostalgia for a British Imperial past. Competing with fantasies from a failed 1970s ideology.
The Lib Dem finance spokesman is insisting that staying in the EU would produce a "Remain bonus".
He will say: "Brexit is already costing the economy £1 billion a week. And the future cost to Britain in lower economic growth could be even higher, if Brexit were actually to happen.
"That's why the election debate on the economy and public spending has Brexit at its heart. For the plain fact is, no party's economic plan is remotely credible unless it starts with stopping Brexit.
"With stopping Brexit as our number one economic policy, Liberal Democrats won't just grow the economy faster, but we'll generate a £50 billion Remain bonus - to pay for our huge extra investment in schools and our policies to tackle inequality."
Shaun Connolly is the PA political correspondent. Image: Liberal Democrats.