In a keynote address to the party’s spring conference in York on Sunday, Sir Ed says Boris Johnson’s “botched” Brexit deal has been a disaster for UK business.
He would argue that the country needs a more ambitious agenda than what Rishi Sunak called the goal of “mere economic survival”.
His attack comes as MPs prepare to vote this week on a key part of Mr Sunak’s revised deal with Brussels on a post-Brexit trading arrangement in Northern Ireland.
I don’t need to tell you what a disaster the Conservative deal with Europe has been for our country.
Ministers hope the Windsor Framework will pave the way for better relations with the EU after the turmoil of recent years.
Sir Ed says, however, that a more radical approach is needed if Britain is to enjoy a “strong and sustainable” economy.
“If you want to boost our economy, you have to fix our broken relationship with Europe,” he said, according to an advance quote from his speech.
“You don’t need me to tell you what a disaster the Conservatives’ deal with Europe has been for our country.
“That is why we campaigned against it. Why, when Boris Johnson brought his terrible deal to Parliament, even supported by Labour, the Liberal Democrats stood alone and voted against it.
“And this is why the Liberal Democrats now have a real plan to fix Britain’s trade – to dismantle the Conservatives’ trade barriers, tear down their red tape, and rebuild relationships of trust and friendship with our European neighbours.”
Sir Ed will also underline his party’s reputation as “proud internationalists” by condemning the government’s “anti-refugee bill”.
He will also attack Mr Sunak’s decision when chancellor to abandon a commitment first introduced by the Conservative-Lib Dem coalition – to devote 0.7% of national income to international aid.
“Our 0.7% pledge has survived three Conservative chancellors. But then came Rishi Sunak, lifting a proud pledge that Britain would lead the world in aid for the poorest. How cruel, counterproductive, and unpatriotic,” he will say.
“So Liberal Democrats, we will put the UK where it is. Leading the fight against poverty, hunger and disease – everywhere in the world.”
