Business executives in the U.K. have been warned that their companies will face a serious penalty for failing to help tackle the climate crisis.

John McDonnell, shadow chancellor for the British Labour Party, threatened to delist publicly traded corporations for not pulling their weight.

Britons go to the polls in a general election on December 12.

"The existential threat of climate change is Labour's overriding priority when we enter government," McDonnell said today. "If we are to meet the climate change target to keep global warming to 1.5 degrees above pre-industrial levels, we need to ensure that companies are also working alongside government. Many now are. 

"But business bodies themselves are calling for companies to improve climate-related financial reporting and for all companies to bring forward their decarbonization plans. And we support those proposals," he continued. "But for those companies not taking adequate steps under Labour, we believe they should be delisted from the London Stock Exchange.

"And the corporate governance code and legislation will be amended to set out minimum standards for listing, related to evidence the action being taken to tackle climate change."

McDonnell also raised concerns about excessive pay, calling it "obscene" that billionaires are "buying access and tax breaks" from Boris Johnson's Conservative party.

"We're offering real change for our country, putting wealth and power in the hands of the many, not just the few," McDonnell said.

He pointed out that in the first three working days of 2019, "the U.K.'s top executives made more money than the full-time worker—typical full-time worker—will earn in the entire year."

After highlighting the gender-pay gap, McDonnell also noted that a median hourly pay differential of 21.7 percent between white people and people from all ethnic minorities in London.

He said it "cannot be right" to have these levels of discrimination on race and gender. And that this wealth of a company needs to be distributed more equitably.

"That's why Labour is committed to introducing an excessive pay levy on companies and will bring in a 20:1 pay ratio between the lowest and highest paid employees in the public sector," McConnell declared. "We'll also move towards a 20:1 pay ratio between the lowest and highest paid employees in companies bidding for public-sector contracts."

A company paying a living wage of just over 16,000 pounds per year to a worker could pay an executive 350,000 pounds per year if it wanted to obtain a public-sector contract.

"All large companies will be required, as part of annual reporting, to disclose the total of CEO remuneration to median employee pay and yes, the steps they're taking to reduce it," he added. "Directors will be required to explicitly state in their annual report that no employee has received pay less than the real living wage, which will be a statutory requirement under a Labour government."