Business leaders have deserted Rishi Sunak for Keir Starmer, a new poll shows.
The Labour Party has a record lead over the Conservatives among industry leaders, Savanta found.
It comes after Sir Keir said that “wealth creation” was his top priority.
Labour has been courting business bosses for months, in a bid to seize the mantle of the "party of business" from the Conservatives.
But earlier this week a public letter signed by 120 company chiefs in support of the party caused controversy after some signatories were allegedly associated with dormant firms.
The new poll shows that, of 1,000 business decision makers, 49 per cent see Labour as 'best for business in the UK' compared to 32 per cent who chose the Tories, the biggest gap the polling firm has ever recorded.
Sir Keir was also 15 points ahead of Mr Sunak, on 46 per cent to 31 per cent, with Rachel Reeves and Jeremy Hunt closer on 32 per cent to 29 per cent.
On Saturday Sir Keir said his "number one mission is wealth creation" in what was widely seen as a pitch to the middle classes and the middle ground.
"I think you win from the centre ground, the centre ground is where most people are,” he said in an interview with the Times.
"As a nation, broadly speaking we're a pretty reasonable, tolerant bunch but we are in the centre ground of politics. People don't like the extremes of the right or the left.
"They are reasonably tolerant. They want themselves, their families and the country to improve and make progress."
Chris Hopkins, political research director at Savanta said: “One of the key tests of this election will be who the public trusts with the UK economy, and business support is a key litmus test of economic credibility, in particular for the Labour Party."
"This election will be won by voters, not business leaders, but the change in business opinion towards the Labour Party and its leaders has been nothing short of transformational.”
